If your database still doesn’t have a user who you want to assign as an employee or administrator, then you can assign a relevant type to him when adding him.
Administrator - is a user who has all rights (like account owner has too) except a right to set up an account. Check this article to find out how to grant this right.
Please note that registering administrators with emails such as yopmail* and maildrop* is forbidden. If you try to log in with such email address you will get a message that email address is not safe.
By default, an employee doesn’t have additional rights, but you can grant them.
You also can assign an employee as a manager.