This is question 22 on the paper FAFSA.

If you are a male (age 18-25) and not registered with Selective Service, select Register Me and Selective Service will register you. You can also register over the Internet at www.sss.gov.

If you believe that you are not required to register with Selective Service, you should call the Selective Service office at 1-847-688-6888 for information regarding exemptions or visit the Selective Service Web site at www.sss.gov.