To apply for Original Medicare (Parts A and B) ONLINE, Visit Social Security online https://www.ssa.gov/benefits/medicare/ and follow the instructions. The application takes less than 10 minutes. After you submit the application, you will get a receipt and an application number you can use to check the status of your application later. Once you are enrolled, Social Security will send you a Welcome to Medicare packet that includes your Medicare card. BY PHONE Call the Social Security national customer hotline at 800-772-1213. IN PERSON Visit your local Social Security office.