Frameguard mitigates clickjacking attacks by setting the X-Frame-Options header.
Attackers get you to click on something you do not wish to click on. Often they do this by iframing other website, buttons but with a different context.
For example lets say your button says you are only going to vote democrat, hackers may make a website that says you will only vote republican and iFrame your button in their website.
The X-Frame-Options header tells browsers to prevent your webpage from being put in an iframe. This can also control which domains are allowed to load iframes from your site.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseFrameGuard(new FrameGuardOptions("http://amazon.com"));
}