Lock a domain in Apple Business Manager
When a domain is locked, only Managed Apple Accounts can be created using the verified domain. Personal Apple Accounts can’t be created on this domain and existing Apple Accounts created before enabling the lock remain in place, unless Domain Capture is initiated. This option helps to ensure that moving forward, all accounts using the domain are organizationally owned.
Important: Locking a domain prevents anyone from creating a personal Apple Account using that domain and can’t be turned off unless the domain is removed.
Lock a domain
In Apple Business Manager
, sign in with a user that has the role of Administrator or People Manager.Select your name at the bottom of the sidebar, select Preferences
, then select Managed Apple Accounts 
.In the Domains section, select the domain you want to lock, select Manage, then lock the domain.
Read the information carefully, the only way to unlock a domain is to remove it from Apple Business Manager.
Important: Locking a domain permanently prevents anyone from creating an Apple Account using that domain.
Select Lock Domain.
Do one of the following:
Close the window if you want to begin the domain capture process or federation process at a later time.
Federate the domain.
Select Get Started with Domain Capture to begin the domain capture process. See Capture a domain.
If you locked this domain in error, see Remove a domain.