Adding restrictions will require registrants to submit certain pieces of information along with their registration form. In addition, you can put limits on the number of teams, participants, etc can register through the form. Anyone past the limits set will automatically be put on a waitlist. 

Pro Tip: adding restrictions will make a form longer to fill out. If you are looking for a more basic form with less questions, flip these to No and the question won’t be asked on your form.