Medicare is a federal program that offers health insurance to American citizens and other eligible individuals based on age, disability or a qualifying medical condition.

Medicare is individual insurance and doesn’t cover spouses or dependents.

To be eligible for Medicare, you must be a U.S. citizen or legal resident. Legal residents must live in the U.S. for at least 5 years in a row, including the 5 years just before applying for Medicare. And, you must meet one of these requirements:

• Age 65 or older

• Younger than 65 with a qualifying disability

• Any age with a diagnosis of end-stage renal disease or ALS

There are four parts of Medicare: Part A, Part B, Part C, and Part D.

Part A provides inpatient/hospital coverage.

Part B provides outpatient/medical coverage.

Part C offers an alternate way to receive your Medicare benefits called Medicare Advantage.

Part D provides prescription drug coverage.

Original Medicare (Parts A & B) helps pay for doctor visits and hospital stays, but it doesn’t cover everything. Many people choose additional coverage by enrolling in one or more private Medicare or Medicare-related plans, including:

Medicare Advantage plans (Part C) combine Part A, Part B and often prescription drug coverage (Part D). Some plans may offer additional benefits like coverage for routine vision and dental care.

Prescription drug plans (Part D) help pay for medications prescribed by a doctor or other health care professional.

Medicare supplement insurance plans (Medigap) help pay some of the out-of-pocket costs not paid by Original Medicare.

Original Medicare is managed directly by the federal government. Medicare Parts C (Medicare Advantage Plans) and Part D (Prescription Drug Plans) are managed by private insurance companies that are contracted with Medicare and authorized to sell Part C and D insurance coverage. Medicare supplement insurance plans or Medigap policies are sold by private insurance companies and often regulated by states' Department of Insurance.

• Most people sign up for both Part A (Hospital Insurance) and Part B (Medical Insurance) when they’re first eligible (usually when they turn 65). It's important to sign up promptly to avoid gaps in coverage or late enrollment penalties. However, if you're already covered through an employer group health plan, it might make sense to sign up for Medicare later or delay Part B. If you are age 65 or older and receive Social Security benefits, you will be automatically enrolled in Part A.

• You need to enroll in Medicare yourself if you aren’t receiving Social Security benefits when you become eligible. Go to ssa.gov/benefits/medicare to enroll online, or call or visit your local Social Security office.