You may want to create a Custom Field and present the user with a list of items to select from. For example:
A dance school may want to create a list of dance styles that a student and staff member have learned. A Dance school may want to create custom lists to describe the student size for ordering costumes.
A music school may want to present a list on Instruments that a student or staff can play.
A Martial Arts school may want to list the belts that a student and staff have completed.
When creating a custom field that utilizes a list, it is important to determine if only one items from the list can be selected, or multiple items. If only 1 item from the list can be selected, you will want to create a "Radio List" or a "Drop Down List". If more than 1 item can be selected, you should create a "Check Box List".