Create Managed Apple IDs in Apple Business Manager
In Apple Business Manager you can create Managed Apple IDs for user accounts.
Managed Apple IDs, roles and passwords
When you create each account, you assign a role that defines the privileges for that account. See Role privileges.
Create new Managed Apple IDs with verified domain names
In Apple Business Manager , sign in with an account that has the role of Administrator or People Manager.
Tap Accounts in the sidebar, then search for an account in the Search field. See How to search.
Select the users from the list.
Tap Edit in the Account row, then tap the Add button to select what the Managed Apple ID will start with.
You can also enter text, such as a full stop, in the field.
Select a domain from the list, then tap Continue.
Tap Close or wait until the activity has finished, then tap Done.