Hi @miffy1200,
This is a great question. You have come to the correct place for help, and I would be glad to share some insight!
Adding an Access ID for other users is a great way to make account management easier. For security purposes, the primary user will receive a notification upon creating a new Access ID if they have the billing notifications enabled.
For more information and details on Access IDs, please visit this link. You can also see more details about billing notifications here.
Let us know if this helps! Best regards.
Adrian, AT&T Community Specialist