If you are eligible for Medicare, you should not use the Marketplace to get health and drug coverage, with two exceptions. If you are eligible for Medicare because you have End-Stage Renal Disease (kidney disease that requires dialysis or transplant) or you have to pay a premium for Medicare Part A (hospital insurance), you can choose to enroll in a Marketplace plan instead of Medicare.
You do not buy a Medicare Advantage Plan, Part D prescription drug plan, or Medicare supplemental insurance (known as Medigap) through the Marketplace. It is illegal for someone to sell you a Marketplace plan if they know you are enrolled in Medicare. If someone tries to sell you a Marketplace plan, let them know that you have Medicare and cannot enroll in a Marketplace plan.