Medicare is broken into parts.
The first step is to get registered for Part A. Part A covers hospitalization. This is usually free to all citizens.
Next is adding Part B. Part B covers medical services outside the hospital like doctor visits, lab tests, and outpatient services. This is available after Part A but there is a cost. The cost is normally taken out of your Social Security payment but needs to be paid for if you are not on Social Security.
From here there is a choice:
Set up an appointment to discuss these and other questions about which is the best plan for you.