Medicare is a federal health-insurance programme for those aged 65 and up that covers the majority of their medical expenses. It covers the costs of health care for some disabled people under the age of 65. Supplemental insurance for Medicare (also known as Medigap insurance) bridges the gap between what Medicare pays and what must be payed out for deductibles, coinsurance, and copayments. Only services that Medicare deems medically necessary are covered by Medigap plans, and payments are usually based on the Medicare-approved fee. Some plans provide benefits not available through Medicare, like as emergency care in a foreign nation.