Close content gap for format mapping parameter

_field-types/mapping-parameters/format.md

@@ -0,0 +1,52 @@
+---
+layout: default
+title: format 
+parent: Mapping parameters
+grand_parent: Mapping and field types
+nav_order: 55
+has_children: false
+has_toc: false
+---
+
+# Format
+
+The `format` parameter is used in mapping to specify how date values should be parsed and formatted in JSON documents. In OpenSearch, dates are represented as strings, and the `format` parameter allows you to define how these strings should be interpreted.
+
+OpenSearch provides a set of preconfigured formats to recognize and parse date strings into long values representing milliseconds-since-the-epoch in UTC. Custom date formats can be specified using the `yyyy/MM/dd` syntax. See [Date field type]({{site.url}}{{site.baseurl}}/field-types/supported-field-types/date/) for more information.
+
+---
+
+## Example: Mapping various date fields
+
+The following example request shows different date formats:
+
+```json
+PUT my_index-003
+{
+  "mappings": {
+    "properties": {
+      "created_at": {
+        "type": "date",
+        "format": "strict_date_optional_time||epoch_millis"
+      },
+      "updated_at": {
+        "type": "date",
+        "format": "yyyy-MM-dd'T'HH:mm:ss.SSSZ||epoch_millis"
+      },
+      "release_date": {
+        "type": "date",
+        "format": "yyyy-MM-dd||MM/dd/yyyy"
+      },
+      "expiration_date": {
+        "type": "date",
+        "format": "strict_date||epoch_second"
+      },
+      "last_login": {
+        "type": "date",
+        "format": "basic_date_time||epoch_millis"
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}