You can apply during your Initial Enrollment Period, a seven-month window that opens three months before you turn 65, includes your birthday month, and closes three months after.

The easiest way is online at SSA.gov. You can also call Social Security at 1-800-772-1213 or visit your local Social Security office.

If you are already receiving Social Security benefits, you will be enrolled in Original Medicare automatically. If you are not, you need to sign up yourself during your Initial Enrollment Period.

You can sign up during the General Enrollment Period, which runs January 1 through March 31 every year. Your coverage becomes effective the first day of the month after you enroll.

Yes. If you do not sign up for Part B when you are first eligible and you do not have other creditable coverage, a late enrollment penalty is added to your premium for as long as you have Part B. Part D has a separate late enrollment penalty that works the same way.

Yes. Order a replacement by calling 1-800-772-1213 or through the Social Security Administration website. Have your Medicare number ready when you call.