Medicare and ACA
Many people have coverage through the healthcare marketplace
Once you are eligible for Medicare, you must discontinue your coverage by your Medicare start date and go onto medicare.
If you are receiving social security you would receive a Medicare card about 3 months before you turn 65, if not you would have to enroll in Medicare.
You would be on Medicare A and B and during your initial enrollment period you can choose to add a Medicare supplement or enroll in a Medicare Advantage plan.