Limit enrollment on your courses/degrees/membership/bundle courses can be done easily in the following steps.
1. Click on Commerce to the left and then click Courses.
2. Click on Edit.
3. Look for Maximum Enrollments.
4. Add the number of clients who wants to enroll as you prefer.
5. Hit Save when done.
6. This can be carried out for same steps for your memberships, degrees, and course bundles