Upon turning 65 years old, you'll be eligible for Medicare coverage, as a way to supplement or completely replace you existing health insurance coverage. Through the use of your Medicare card, the government provides Original Medicare at this time; also known as Medicare Part A and Medicare Part B. 

In addition, you have two options to further enhance your Medicare coverage. 

1) Medicare Part C or Medicare Advantage- Health Insurance plans provided by private insurance companies that offer at least the same level of benefits of Original Medicare but can also include additional ancillary services and protections. With this arrangement, you forfeit Original Medicare as your network and agree to accept the terms and conditions of the private insurance company's provider network. 

2) Medicare Supplement Insurance or Medigap- Administered by various private insurance companies, different coverage levels will help pay for additional out-of-pocket costs not covered by Original Medicare. Typically, the more expensive the Medigap plan is in premium( denoted by letters such as Plan F or Plan K), the more of Original Medicare it covers. 

With Medigap, you might have to buy Part D coverage as well. Part D coverage helps cover the costs of prescription drugs for Medicare-eligible consumers.