Emad's Blog

In Microsoft flow there is no built in action to add a user to a SharePoint group. One way to achieve this is to use the “Send HTTP request to SharePoint”

in this action you need to

1. Set the URL of the Site
2. Set method to “POST”
3. URI set to “_api/web/sitegroups({GROUPID})/users”, example: _api/web/sitegroups(10)/users
4. Add header with key=”accept” and value = “application/json;odata.metadata=none”
5. Add header with key =”content-type” and value = “application/json”
6. Set the Body to be {‘LoginName’:’i:0#.f|membership|[EMAIL ADDRESS]’}, example: {‘LoginName’:’i:0#.f|membership|john.doe@domain.onmicrosoft.com’}

It would look like this

This is tested with a SharePoint online connection but assume might work with on premise SharePoint as well.