Bulk import group members (preview) in Azure Active Directory
Using Azure Active Directory (Azure AD) portal, you can add a large number of members to a group by using a comma-separated values (CSV) file to bulk import group members.
To bulk import group members
Sign in to the Azure portal with a User administrator account in the organization. Group owners can also bulk import members of groups they own.
In Azure AD, select Groups > All groups.
Open the group to which you're adding members and then select Members.
On the Members page, select Import members.
On the Bulk import group members (Preview) page, select Download to get the CSV file template with required group member properties.
Open the CSV file and add a line for each group member you want to import into the group (required values are either Member object ID or User principal name). Then save the file.
On the Bulk import group members (Preview) page, under Upload your csv file, browse to the file. When you select the file, validation of the CSV file starts.
When the file contents are validated, the bulk import page displays File uploaded successfully. If there are errors, you must fix them before you can submit the job.
When your file passes validation, select Submit to start the Azure bulk operation that imports the group members to the group.
When the import operation completes, you'll see a notification that the bulk operation succeeded.
Check import status
You can see the status of all of your pending bulk requests in the Bulk operation results (preview) page.
For details about each line item within the bulk operation, select the values under the # Success, # Failure, or Total Requests columns. If failures occurred, the reasons for failure will be listed.
Bulk import service limits
Each bulk activity to import a list of group members can run for up to one hour. This enables importation of a list of at least 40,000 members.