Smart Enrolments let admins automate the course enrolment process by linking courses to segments.
Once users are organised into segments, you can set specific courses to be automatically assigned to all users in a segment. Any new user added to the segment is automatically enrolled on all courses linked to that segment. If a user is removed from the segment, they're unenrolled from all courses linked to it.
Note: To set up Smart Enrolments for a course, its enrolment method must be set to By assignment only.
When you're ready to set Smart Enrolment up, see How do I add or remove a Smart Enrolment?