To enroll in a Medicare supplement plan, you must be over 64 1/2 years old and be covered under Medicare. Supplemental plans do not work with any other kind of health coverage including VA benefits, TRICARE, Medicare Advantage, union or employer group coverage. It is designed only for persons on Medicare or about to go on Medicare.
In every supplemental Plan, benefits must be identical, from every company providing it. There are different types of plans, but they must be the same from company to company. However, the premiums will vary for the plans between companies. Medicare supplemental plans are structured in standard packages (Plans A through L), making pricing comparisons easier for consumers. You should study them and pick a plan that will be a good fit for you.
This coverage is provided by individual private insurance companies that you have most likely done business with throughout your lifetime. Names you would recognize would be United Health Care, Blue Cross/Blue Shield, Humana and others. Please keep in mind that the supplemental providers must sell you an Medicare policy with exactly the same benefits as every other company so you can compare them easily on the basis of price only.
The only exception to the rules would be where your state, such as Massachusetts, Minnesota, and Wisconsin, require another type of Medicare supplemental plan. (Medigap Select) This plan has requirements of it’s own. These plans may make you use a named hospital and will in some situations state you use named physicians in order to obtain complete benefits.