How do I change my Apple ID in macOS? (no Apple ID login) When I setup my user, I used my old company email. I no longer have access to that email. I do, though, have full admin access to my current user (and all users for that matter).

Currently, I'm trying to update Xcode, but it requires the Apple ID credentials with which it was originally installed. I no longer have them.

How can I use my admin position to change my Apple ID?
The easiest is simply to uninstall Xcode, log out of the App Store with your AppleID, login again with a new AppleID - and simply reinstall Xcode.

If you do not have an AppleID, you can create a new one. Xcode is a free download.