If you are over the age of 25, you can no longer register for the selective service and will need to write a letter (likely to a case manager or federal office) explaining why you did not register. The reasoning must be strong and valid in order to be accepted.
If you are between the ages of 18-25, go to the Selective Service website. You can use your social security number and date of birth in order to make sure that you have not been registered for the selective service draft.
Once you have confirmed that you have not registered, click on the "Registration Info" tab and you will be directed to a page with a hyperlink called "register Now!"
On the resulting page, scroll down in order to find the Selective Service online registration form.
Fill out your address, date of birth, and valid social security number. Make sure to also include where you learned about selective service.
Once you have filled out the online registration, select "Submit Registration". You will be taken to a page that will serve as your proof of Selective Service registration that will be honored by federal offices, allowing you to become eligible for government scholarships, worker retaining, and other forms of government financial support.