Should email link in invitation always match the email address entered when adding user?
Yes, the invitation email should match the email address you've entered, @1padmaker3.
I've added a screenshot to better illustrate how the invitation works.
Once your authorized user accepts the invitation, they'd be ask to create an account. The email address will automatically populate in the Create Account page. Also, it will be come the automatic username of the user.
Also, I've added these articles to help you manage your authorized users in QuickBooks: