If you are not collecting Social Security benefits when you turn 65 and become eligible for Medicare, you have to file a separate application for Medicare.
So howdo you enroll in Medicare if you aren't yet claiming your Social Security retirement or other Social Security benefits when you turn 65? Until recently, in that situation you had to sign up for Medicare in person, at a local Social Security office. But now, instead, you can apply entirely online. (Even though you're not applying for Social Security benefits yet, you apply for Medicare through Social Security.) Medicare provides a very simple online Medicare-only application. The form is easy, and once you complete it you don't have to do anything else. Medicare will send you your Medicare enrollment card within a few weeks. Once you are enrolled, Medicare will send you a bill for your monthly Part B premium ($96.40 per month for most people), which you can pay with a check. (Most people have no premium to pay for Medicare Part A.).
You should apply for Medicare three months before the month you turn 65. That will ensure that your Medicare coverage will begin when you turn 65. If you wait until you actually turn 65 before you apply, your Medicare coverage start date might be delayed.
Once you are enrolled in Medicare, paying is simple -- Medicare will send you a bill for your monthly Part B premium ($96.40 per month for most people), which you can pay with a check. (Most people have no premium to pay for Medicare Part A.) Once you do claim Social Security benefits, Medicare will deduct your Part B premium directly from your Social Security benefits check. If you also join a Medicare Part C Medicare Advantage plan, the plan will send you a separate bill for its monthly premium.