Enabling enrollment allows new users to request accounts in the internal database. By default, the only identity source that you can select to enable enrollment is the internal database. Users cannot enroll in any external identity sources.
In the Security Console, click Setup > Self-Service Settings.
Click Select identity sources.
In the Display Name for Identity Source Selection Component field, enter user-friendly text about choosing an identity source.
Select Allow users to request accounts in this identity source to make the internal database available to users at enrollment.