ZZZ ‐ [Archived] ‐ Configure Outlook Add in capability within your Teams app

Important

Content in this document has been moved to Teams platform documentation. Please do not refer to or update this document.

Configure Outlook Add-in capability within your Teams app

Introduction

Office Add-ins are web apps that extend the functionality of Outlook. Some of the things that can be done with an Outlook Add-in:

Read and write the content of email messages and meeting invitations, as well as responses, cancellations, and appointments.
Read properties of the user's mailbox.
Respond automatically to events, such as the sending of an email.
Integrate with external services including CRM and project management.
Add custom ribbon buttons or menu items to perform specific tasks.

For more information, start with Outlook Add-ins Overview.

Prerequisites

To configure an Office Add-in as additional capability, you must meet the following conditions:

You have a Microsoft 365 account that includes Teams, or separate subscriptions to both Microsoft 365 and Teams, to test the application. For example, an *.onmicrosoft.com account.
Your Microsoft 365 account has been added as an account in desktop Outlook. See Add an email account to Outlook
To deploy the Teams app to Azure as described in the last section of this article, you need an Azure account to an Azure subscription. Create your free Azure account if you don't already have one by using the link Free Azure account.

Overview

The following are the major steps to adding an Outlook Add-in to a Teams app. Details are in the sections below.

Prepare the Teams app project
Create an Office Add-in project that is initially separate from your Teams app project.
Merge the manifest from the Outlook Add-in project into the unified Microsoft 365 manifest.
Copy the Outlook Add-in files to the Teams app project.
Edit the tooling configuration files.
Run the app and add-in locally at the same time
Move the application to Azure.

Prepare the Teams app project

Begin by separating the source code for the tab (or bot) into its own subfolder. These instructions assume that the project initially has the following structure. To create a Teams app project with this structure, be sure you are using the latest released version of Teams Toolkit.

|-- .vscode/
|-- appPackage/
|-- build
|-- env/
|-- infra/
|-- node_modules/
|-- src/
|-- .gitignore
|-- .localConfigs
|-- .webappignore
|-- package-lock.json
|-- package.json
|-- teamsapp.local.yml
|-- teamsapp.yml
|-- tsconfig.json
|-- web.config

NOTE: If you are working with a new Teams tab project, the node_modules folder and the package-lock.json file will not be present. The node_modules is created in a later step when you run npm install in the root of the project. The build folder will not be present unless and until you run a build script on the project.

Create a folder under the root named "tab" (or "bot").

NOTE: For simplicity, the remainder of this article assumes that the existing Teams app is a tab. If you started with a bot instead, replace "tab" with "bot" in all of these instructions, including the content you add or edit in various files.
Copy the infra folder into the new subfolder, and then delete the azure.parameters.json file from the new tab/infra folder.
Move the node_modules and src folders into the new subfolder.

Move the .webappignore, package-lock.json, package.json, tsconfig.json, and web.config files into the new subfolder.

|-- .vscode/
|-- appPackage/
|-- build
|-- env/
|-- infra/
|-- tab/
|-- |-- infra/
|-- |-- node_modules/
|-- |-- src/
|-- |-- .webappignore
|-- |-- package-lock.json
|-- |-- package.json
|-- |-- tsconfig.json
|-- |-- web.config
|-- .gitignore
|-- .localConfigs
|-- teamsapp.local.yml
|-- teamsapp.yml

In the package.json that you just moved to the tab folder, delete the script named "dev:teamsfx" from the "scripts" object. This script is added to a new package.json in the next step.

Create a new file named package.json in the root of the project and give it the following content:

{
    "name": "CombinedTabAndAddin",
    "version": "0.0.1",
    "author": "Contoso",
    "scripts": {
        "dev:teamsfx": "env-cmd --silent -f .localConfigs npm run start:tab",
        "build:tab": "cd tab && npm run build",
        "install:tab": "cd tab && npm install",
        "start:tab": "cd tab && npm run start",
        "test": "echo \"Error: no test specified\" && exit 1"
    },
    "devDependencies": {
        "@microsoft/teamsfx-cli": "2.0.2-alpha.4f379e6ab.0",
        "@microsoft/teamsfx-run-utils": "alpha",
        "env-cmd": "^10.1.0",
        "office-addin-dev-settings": "^2.0.3",
        "ncp": "^2.0.0"
    }
}

Change the "name", "version", and "author" properties, as needed.
Open the teamsapp.yml file in the root of the project and find the line ignoreFile: .webappignore. Change this to ignoreFile: ./tab/.webappignore.
Open the teamsapp.local.yml file in the root of the project and find the line args: install --no-audit. Change this to args: run install:tab --no-audit.
Open TERMINAL in Visual Studio Code. Navigate to the root of the project and run npm install. Among other things, a new node_modules folder and a new package.lock.json file are created in the project root.
Next run npm run install:tab. Among other things, a new node_modules folder and a new package.lock.json file are created are created in the tab folder, if they aren't there already.
Verify that you can sideload the tab with the following steps:
1. Open Teams Toolkit, and in the ACCOUNTS section, verify that you are signed into Microsoft 365.
2. Select View | Run in Visual Studio Code.
3. In the RUN AND DEBUG drop down menu, select the option, Debug in Teams (Edge), and then press F5. The project will build and run. This process may take a couple of minutes. Eventually, Teams opens in a browser with a prompt to add your tab app.
  
  Note: If this is the first time you've debugged a Teams app on this computer, you will be prompted to install an SSL certificate. Select Install and then Yes to the second prompt. Login to your Microsoft 365 account if you are prompted to do so.
4. Select Add.
5. To stop debugging and uninstall the app, select Run | Stop Debugging in Visual Studio Code.

Create an Outlook Add-in project

Open a second instance of Visual Studio Code.
With Teams Toolkit open in Visual Studio Code, select Create a new app.
In the Select an option drop down, select Outlook add-in, and then select Taskpane.
Select the folder where you want to create the add-in.
Give a name (with no spaces) to the project when prompted and Teams Toolkit will create the project with basic files and scaffolding and open it in a separate Visual Studio Code window. You will used this project as a source for files and markup that you add to the Teams project.
Although you won't be developing this project, verify that it can be sideloaded from Visual Studio Code before you continue. Use the following steps:
1. First, make sure Outlook desktop is closed.
2. In Visual Studio Code, open the Teams Toolkit.
3. In the ACCOUNTS section, verify that you are signed into Microsoft 365.
4. Select View | Run in Visual Studio Code. In the RUN AND DEBUG drop down menu, select the option, Outlook Desktop (Edge Chromium), and then press F5. The project builds and a Webpack dev-server window opens. This process may take a couple of minutes. Eventually, Outlook desktop will open.
5. Open the Inbox of your Microsoft 365 account identity and open any message. A Contoso Add-in tab with two buttons will appear on the Home ribbon (or the Message ribbon, if you have opened the message in its own window).
6. Click the Show Taskpane button and a task pane opens. Click the Perform an action button and a small notification appears near the top of the message.
7. To stop debugging and uninstall the add-in, select Run | Stop Debugging in Visual Studio Code. If the Webpack dev-server window does not close, open the Visual Studio Code TERMINAL in the root of the project and run `npm stop`.

Merge the manifest

The Teams app's manifest is generated at debug-and-sideload time (or build time) from the file manifest.json in the \appPackage folder of the Teams project. This file is actually a kind of template for a manifest. In this article it is referred to as the "template" or "manifest template". Most of the markup is hardcoded into the template, but there are also some configuration files that contain data that gets injected into the final generated manifest. In this procedure, you do the following:

Copy markup from the add-in's manifest to the Teams app's manifest template.
Edit the configuration files.

Unless specified otherwise, the file you change is \appPackage\manifest.json.

Copy the "$schema" and "manifestVersion" property values from the add-in's manifest to the corresponding properties of the Teams app's manifest template file.
Adjust the "name.full", "description.short", and "description.full" property values as needed to take account of the fact that an Outlook add-in is part of the app.
Do the same for the "name.short" value. We recommend that you keep the ${{TEAMSFX_ENV}} on the end of the name. This variable is replaced with "local" when you are debugging on localhost and with "dev" when you are either debugging from a remote domain or in production mode. (Historically, Office Add-in developer documentation has used the term "dev" or "dev mode" to refer to running the add-in on a localhost. It has used the term "prod" or "production mode" to refer to running the add-in on a remote host for staging or production. Teams developer documentation has used the term "local" to refer to running the add-in on a localhost, and the term "dev" to refer to running the add-in on a remote host for remote debugging, which is usually called "staging". We are working on getting the terminology consistent.)

The following is an example:
```
"short": "Contoso Tab and Add-in-${{TEAMSFX_ENV}}",
```
Notes: The "name.short" value appears in both the Teams tab capability and the Outlook add-in. Examples:
- It is the label under the launch button of the Teams tab.
- It is content of the title bar of the add-in's task pane.
If you changed the "name.short" value from its default (which is the name of the project followed by the ${{TEAMSFX_ENV}} variable), make exactly the same change in all places where the project name appears in the following two files in the root of the project: teamsapp.yml and teamsapp.local.yml.
If there is no "authorization.permissions.resourceSpecific" array in the Teams manifest template, copy it from the add-in manifest as a top-level property. If there already is one in the Teams template, copy any objects from the array in the add-in manifest to the array in the Teams template. The following is an example:
```
"authorization": {
    "permissions": {
        "resourceSpecific": [
            {
                "name": "MailboxItem.Read.User",
                "type": "Delegated"
            }
        ]
    }
},
```
In the env/.env.local file, find the lines that assign values to the TAB_DOMAIN and TAB_ENDPOINT variables. Add the following lines immediately below them:
```
ADDIN_DOMAIN=localhost:3000
ADDIN_ENDPOINT=https://localhost:3000
```
In the env/.env.dev file, add the following line just below the TAB_ENDPOINT= ... line:
```
ADDIN_ENDPOINT=
```
In the Teams manifest template, add the placeholder "${{ADDIN_DOMAIN}}", to the top of the "validDomains" array. The Teams Toolkit will replace this with a localhost domain when you are developing locally. When you deploy the finished combined app to staging or production as described below in Move the application to Azure, Teams Toolkit will replace the placeholder with the staging/production URI. The following is an example:
```
"validDomains": [
    "${{ADDIN_DOMAIN}}",
    
    // other domains or placeholders
],
```
Copy the entire "extensions" property from the add-in's manifest into the Teams app manifest template as a top-level property.

Copy the Outlook Add-in files to the Teams app project

Create a top-level folder called "add-in" in the Teams app project.
Copy the following files and folders from the add-in project to the "add-in" folder of the Teams app project.
- /appPackage
- /infra
- /src
- .eslintrc.json
- babel.config.json
- package-lock.json
- package.json
- tsconfig.json
- webpack.config.js

When you have finished the copy, delete the manifest.json file in the /add-in/appPackage folder.

Your folder structure should now look like the following:

|-- .vscode/
|-- add-in/
|-- |-- appPackage/assets/
|-- |-- infra/
|-- |-- src/
|-- |-- .eslintrc.json
|-- |-- babel.config.json
|-- |-- package-lock.json
|-- |-- package.json
|-- |-- tsconfig.json
|-- |-- webpack.config.js
|-- appPackage/
|-- build\appPackage/
|-- env/
|-- infra/
|-- node_modules/
|-- tab/
|-- |-- infra/
|-- |-- node_modules/
|-- |-- src/
|-- |-- .webappignore
|-- |-- package-lock.json
|-- |-- package.json
|-- |-- tsconfig.json
|-- |-- web.config
|-- .gitignore
|-- .localConfigs
|-- package.json
|-- teamsapp.local.yml
|-- teamsapp.yml

Edit the tooling configuration files

Open the package.json file in the root of the project.

Add the following scripts to the "scripts" object:

"install:add-in": "cd add-in && npm install",
"postinstall": "npm run install:add-in && npm run install:tab",
"build:add-in": "cd add-in && npm run build",
"build:add-in:dev": "cd add-in && npm run build:dev",
"build": "npm run build:tab && npm run build:add-in",

Open the package.json file in the add-in folder (not the tab folder, and not the root of the project).

Three of the scripts in the "scripts" object have a manifest.json parameter like the following.

"start": "office-addin-debugging start appPackage/manifest.json",
"stop": "office-addin-debugging stop appPackage/manifest.json",
"validate": "office-addin-manifest validate appPackage/manifest.json",

In the "start" script, change appPackage/manifest.json to ../appPackage/build/appPackage.local.zip. When you are done, the line should look like this:

"start": "office-addin-debugging start ../appPackage/build/appPackage.local.zip",

In the "validate" and "stop" scripts, change the parameter to ../appPackage/build/manifest.local.json. When you are done, they should look like this:

"stop": "office-addin-debugging stop ../appPackage/build/manifest.local.json",
"validate": "office-addin-manifest validate ../appPackage/build/manifest.local.json",

In Visual Studio Code, open the TERMINAL. Navigate to the add-in folder, and then run the command npm install.
In the add-in folder, open the webpack.config.js file.
Change the line from: "appPackage/manifest*.json", to from: "../appPackage/build/manifest*.json",.
In the root of project, open the teamsapp.local.yml file and find the provision section. Use the # character to comment out the lines that validate the manifest template. This is necessary because the Teams manifest validation system is not yet compatible with the changes you made to the manifest template. When you are done, the lines should look like the following:
```
  # - uses: teamsApp/validateManifest
  #   with:
  #     # Path to manifest template
  #     manifestPath: ./appPackage/manifest.json 
```
Be careful to comment out only the teamsApp/validateManifest section. Do not comment out the teamsManifest/validateAppPackage section!
Repeat the preceding step for the teamsapp.yml file. The three lines are found in both the provision and the publish sections. Comment them out in both places.
Open the .vscode\tasks.json file in the add-in project and copy all of the tasks in the "tasks" array. Add them to "tasks" array of the same file in the Teams project. Do not remove any of the tasks that are already there. Be sure all tasks are separated by commas.

In each of the task objects that you just copied, add the following "options" property to ensure that these tasks run in the add-in folder.

"options": {
    "cwd": "${workspaceFolder}/add-in/"
}

For example, the "Debug: Outlook Desktop" task should like the following when you are done.

{
    "label": "Debug: Outlook Desktop",
    "type": "npm",
    "script": "start",
    "dependsOn": [
      "Check OS",
      "Install"
    ],
    "presentation": {
      "clear": true,
      "panel": "dedicated",
    },
    problemMatcher": [],
    "options": {
        "cwd": "${workspaceFolder}/add-in/"
    }
}

Add the following task to the tasks array in the .vscode\tasks.json file of the project. Among other things, this will create the final manifest.

{
    // Create the debug resources.
    // See https://aka.ms/teamsfx-tasks/provision to know the details and how to customize the args.
    "label": "Create resources",
    "type": "teamsfx",
    "command": "provision",
    "args": {
        "template": "${workspaceFolder}/teamsapp.local.yml",
        "env": "local"
    }
},

Add the following task to the tasks array. Note that it adds a "Start Add-in Locally" task that combines the tab app's "Create resources" task with the add-in's debugging task and specifies that they must run in that order.
```
{
    "label": "Start Add-in Locally",
    "dependsOn": [
        "Create resources",
        "Debug: Outlook Desktop"
    ],
    "dependsOrder": "sequence"
},
```

Add the following task to the tasks array. It combines the "Start Teams App Locally" task with the "Start Add-in Locally" and specifies that they must run in that order.

 {
     "label": "Start App and Add-in Locally",
     "dependsOn": [
         "Start Teams App Locally",
         "Start Add-in Locally"
     ],
     "dependsOrder": "sequence"
 },

Open the .vscode\launch.json file in the project, which configures the RUN AND DEBUG UI in Visual Studio Code and add the following two objects to the top of the "configurations" array.

{
    "name": "Launch Add-in Outlook Desktop (Edge Chromium)",
    "type": "msedge",
    "request": "attach",
    "port": 9229,
    "timeout": 600000,
    "webRoot": "${workspaceRoot}",
    "preLaunchTask": "Start Add-in Locally",
    "postDebugTask": "Stop Debug"
},
{
    "name": "Launch App and Add-in Outlook Desktop (Edge Chromium)",
    "type": "msedge",
    "request": "attach",
    "port": 9229,
    "timeout": 600000,
    "webRoot": "${workspaceRoot}",
    "preLaunchTask": "Start App and Add-in Locally",
    "postDebugTask": "Stop Debug"
},

In the "compounds" section of the same file, rename the "Debug in Teams (Edge)" compound to "Launch App Debug (Edge)", and rename the "Debug in Teams (Chrome)" compound to "Launch App Debug (Chrome)".
Verify that you can sideload the add-in capability of the Teams app to Outlook with the following steps:
1. First, make sure Outlook desktop is closed.
2. In Visual Studio Code, open the Teams Toolkit.
3. In the ACCOUNTS section, verify that you are signed into Microsoft 365.
4. Select View | Run in Visual Studio Code. In the RUN AND DEBUG drop down menu, select the option, Launch Add-in Outlook Desktop (Edge Chromium) (*not* any of the "Launch *App* ..." options), and then press F5. The project builds and a Webpack dev-server window opens. This process may take a couple of minutes. Eventually, Outlook desktop will open.
5. Open the Inbox of your Microsoft 365 account identity and open any message. A Contoso Add-in tab with two buttons will appear on the Home ribbon (or the Message ribbon, if you have opened the message in its own window).
6. Click the Show Taskpane button and a task pane opens. Click the Perform an action button and a small notification appears near the top of the message.
7. To stop debugging and uninstall the add-in, select Run | Stop Debugging in Visual Studio Code. If the Webpack dev-server window does not close, open the Visual Studio Code TERMINAL in the root of the project and run `npm stop`.

Run the app and add-in locally at the same time

You can sideload and run the app and the add-in simultaneously, but the debugger cannot reliably attach when both are running. So to debug, run only one at a time.

To debug the app, see the last step of the Prepare the Teams app project above.

To debug the add-in, see the last step of the Edit the tooling configuration files above.

To see both the app and the add-in running at the same time, take the following steps.

First, make sure Outlook desktop is closed.
In Visual Studio Code, open the Teams Toolkit.
In the ACCOUNTS section, verify that you are signed into Microsoft 365.
Select View | Run in Visual Studio Code. In the RUN AND DEBUG drop down menu, select the option, Launch App and Add-in Outlook Desktop (Edge Chromium), and then press F5. The project builds and a Webpack dev-server window opens to host the add-in. The tab app is hosted in the Visual Studio Code terminal. This process may take a couple of minutes. Eventually, both of the following will happen:
- Teams opens in a browser with a prompt to add your tab app. If Teams has not opened by the time Outlook desktop opens, then automatic sideloading has failed. You can manually sideload it to see both the app and the add-in running at the same time. For sideloading instructions, see Upload your app in Teams. You'll find the manifest.zip file to upload at `C:\Users\{yourname}\AppData\Local\Temp`.
- Outlook desktop opens.
In the Teams prompt, select Add and the tab will open.
In Outlook, open the Inbox of your Microsoft 365 account identity and open any message. A Contoso Add-in tab with two buttons will appear on the Home ribbon (or the Message ribbon, if you have opened the message in its own window).
Click the Show Taskpane button and a task pane opens. Click the Perform an action button and a small notification appears near the top of the message.
To stop debugging and uninstall the add-in, select Run | Stop Debugging in Visual Studio Code. If the Webpack dev-server window does not close, open the Visual Studio Code TERMINAL in the root of the project and run `npm stop`.
If you had to manually sideload the Teams Tab app, remove it from Teams as instructed in a href="https://learn.microsoft.com/en-us/microsoftteams/platform/concepts/deploy-and-publish/apps-upload#remove-your-app">Remove your app.

Move the application to Azure

Open the teamsapp.yml file in the root of the project and find the line deploymentName: Create-resources-for-tab. Change it to deploymentName: Create-resources-for-tab-and-addin.
In the same file, add the following code to the end of the provision: section. Note that indentation is meaningful in YAML, so - uses and - name statements should be indented 2 spaces, with statements should be aligned with uses, and the children of with should be indented a further 2 spaces.
```
provision:

  -- other YAML omitted --

  - uses: azureStorage/enableStaticWebsite
    with:
      storageResourceId: ${{ADDIN_AZURE_STORAGE_RESOURCE_ID}}
      indexPage: index.html
      errorPage: error.html
```

In the same file, replace the entire deploy: section with the following code. These changes take account of the new folder structure and the fact that both add-in and tab files need to be deployed.

deploy:
  - name: InstallAllCapabilities
    uses: cli/runNpmCommand # Run npm command
    with:
      args: install

  - name: BuildAllCapabilities
    uses: cli/runNpmCommand # Run npm command
    with:
      args: run build --if-present

  - name: DeployTab
    uses: azureAppService/zipDeploy
    with:
      artifactFolder: tab
      ignoreFile: ./tab/.webappignore
      # The ID of the cloud resource where the tab app will be deployed.
      # This key will be generated by arm/deploy action automatically.
      resourceId: ${{TAB_AZURE_APP_SERVICE_RESOURCE_ID}} 

  - name: DeployAddin
    uses: azureStorage/deploy
    with:
      workingDirectory: .
      # Deploy base folder
      artifactFolder: add-in/dist
      # The ID of the cloud resource where the add-in will be deployed.
      resourceId: ${{ADDIN_AZURE_STORAGE_RESOURCE_ID}}

Open the infra/azure.parameters.json file in the root of the project and replace its contents with the following JSON.

{
    "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentParameters.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
      "resourceBaseName": {
        "value": "tabandaddin${{RESOURCE_SUFFIX}}"
      },
      "webAppSku": {
        "value": "F1"
      },
      "storageSku": {
        "value": "Standard_LRS"
      }
    }
}

Open the infra/azure.bicep file in the root of the project (not the one in either the tab or add-in subfolders) and replace its contents with the following.

// Params for Teams tab resources
@maxLength(20)
@minLength(4)
@description('Used to generate names for all resources in this file')
param resourceBaseName string
param webAppSku string
param serverfarmsName string = resourceBaseName
param webAppName string = resourceBaseName
param location string = resourceGroup().location
param storageSku string
param storageName string = resourceBaseName

module tabModule '../tab/infra/azure.bicep' = {
  name: 'tabModule'
  params: {
    resourceBaseName: resourceBaseName
    webAppSku: webAppSku
    serverfarmsName: serverfarmsName
    webAppName: webAppName
    location: location
  }
}

module addinModule '../add-in/infra/azure.bicep' = {
  name: 'addinModule'
  params: {
    resourceBaseName: resourceBaseName
    storageSku: storageSku
    storageName: storageName
    location: location
  }
}

// The output will be persisted in .env.{envName}. Visit https://aka.ms/teamsfx-actions/arm-deploy for more details.
output TAB_AZURE_APP_SERVICE_RESOURCE_ID string = tabModule.outputs.TAB_AZURE_APP_SERVICE_RESOURCE_ID // used in deploy stage
output TAB_DOMAIN string = tabModule.outputs.TAB_DOMAIN
output TAB_ENDPOINT string = tabModule.outputs.TAB_ENDPOINT

output ADDIN_AZURE_STORAGE_RESOURCE_ID string =  addinModule.outputs.ADDIN_AZURE_STORAGE_RESOURCE_ID// used in deploy stage
output ADDIN_DOMAIN string = addinModule.outputs.ADDIN_DOMAIN
output ADDIN_ENDPOINT string = addinModule.outputs.ADDIN_ENDPOINT

In Visual Studio Code open the Teams Toolkit and in the ACCOUNTS section be sure you are signed into your Azure account (in addition to being signed into your Microsoft 365 account). For more information about signing in, open Exercise - Create Azure resources to host a Teams tab app and scroll to the Sign in to Azure in Teams Toolkit section.
In the LIFECYCLE section of Teams Toolkit, select Provision. It may take several minutes. You may be prompted to select one of your Azure resource groups.
When provisioning completes, select Deploy to deploy your app code to Azure.

Run the tab capability from the remote deployment

Select View | Run in Visual Studio Code and in the drop down, select one of the following:
- Launch Remote in Teams (Edge)
- Launch Remote in Teams (Chrome)
Press F5 to preview your Teams tab capability.

Run the add-in capability from the remote deployment

Copy the production URL from the ADDIN_ENDPOINT in env/.env.dev file.
Edit \add-in\webpack.config.js file and change urlProd constant value to the value you just copied. Be sure to add a '/' at the end of the URL.
In the Visual Studio Code TERMINAL, navigate to the root of the project, and then run npm run build:add-in.
Copy the file \add-in\dist\manifest.dev.json to the \appPackage folder.
Rename the copy in the \appPackage folder to "manifest.addinPreview.json".
In the TERMINAL, run npx office-addin-dev-settings sideload .\appPackage\manifest.addinPreview.json. This process may take a couple of minutes. Eventually, Outlook desktop will open. (If you are prompted to install office-addin-dev-settings, respond "yes".)
Open the Inbox of your Microsoft 365 account identity and open any message. A Contoso Add-in tab with two buttons will appear on the Home ribbon (or the Message ribbon, if you have opened the message in its own window).
Click the Show Taskpane button and a task pane opens. Click the Perform an action button and a small notification appears near the top of the message.

What’s next

There are other commonly suggested next steps, for example:

Add authentication and make a Graph API call. For the tab capability, see Add single sign-on to Teams app. For the add-in capability, see Enable single sign-on (SSO) in an Office Add-in.
Set up CI/CD pipelines
Call a backend API

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