What's a Virtual user?
Sometimes, you may see a user on your board listed as a virtual user.
Virtual users are placeholder accounts. Trello creates them when you've invited a user to a board or Workspace, but the user hasn't finished the signup process on their own.
Once a user signs up for Trello with the email address that was used to invite them, you'll see the "(Virtual)" change to "Normal" or "Admin," depending on their role.
While a user is a virtual user, you can still add them to cards or boards in order to assign them tasks.