You can change someone’s role to Member, Admin or Owner. Admin’s can access the admin tab and everything else on the platform. And owner has all admin privileges and can delete anyone including other owners. If the role is “Pending” it means a user hasn’t accepted the invite.
You can click on the actions button (three dots) to open a menu. In the menu you can delete users. Deleting users wipes all information (including stars) and isn’t reversible so use with caution.