Administrator ID

Generally speaking if you set up a mac to new or used, correctly, you probably

already have created an Admin user account in that Mac's system.. Also some

users set 'second user account at lower level' and only use Admin for system

upgrade and update; then do not enable automatic login to be more secure.

• How to Add Administrator Accounts to Your Mac - lifewire

https://www.lifewire.com/add-administrator-accounts-to-mac-os-x-2260717

To refresh what that is and how to add or change the account status, there

are several Support articles in the Apple site; and some elsewhere that can

also help understand aspects of this. ~ You may be able to search your Mac

built-in Help to see related articles, online; or Support topics in the Mac.

{The user who already has an Apple ID associated with their own name and

has purchase history, with Apple, could also sign online via icloud; in some

instances, could be useful to restore lost user passwords to owned devices.

That would be separate topic, though related indirectly, to your question.}