A Medicare Supplements are additional insurance policies that Medicare beneficiaries can purchase to cover the gaps in their Original Medicare (Medicare Part A and Medicare Part B) health insurance coverage. plan is additional insurance that works in conjunction with Medicare Part A is hospital coverage for Medicare beneficiaries. It covers inpatient care in hospitals and skilled nursing facilities. It also covers limited home healthcare services and hospice care. and Medicare Part B is medical coverage for people with Original Medicare benefits. It covers doctor visits, preventative care, tests, durable medical equipment, and supplies. Medicare Part B pays 80 percent of most medically necessary healthcare services. benefits. Also known as Medigap, there are 10 standardized plans, A to N. Each lettered plan offers a different level of coverage to suit a variety of needs.