A Medigap plan, or Medicare Supplement, pays after Medicare to help cover your deductibles, copays, and coinsurance that you would otherwise be responsible for. Medigap plans do not replace your Medicare Part B.
Medigap policies are identified by letters A through N. Each policy that goes by the same letter must offer the same basic benefits, and usually the only difference between same-letter policies is the cost. Medicare Supplement Plan F is the most popular policy because of its comprehensive coverage, but as of 2020, Plan F (along with Plan C) is unavailable for new enrollees. The closest substitute for Plan F is Plan G, which pays for everything that Plan F did except the Medicare Part B deductible.