@MANDM123 To add, modify, or delete users who are part of the seed member (test profiles), you can go to “Profiles & Audiences” -> “Test Profiles” and make the necessary changes.
In case you want to do it through a workflow, prepare the list in a CSV or TXT file and use the load activity, update activity, and save audience to create a similar list with updates to the users.
Thanks, Sathees