Does anyone know how Medicare Supplement Insurances work and what are their term? I'm thinking of buying one for my dad because he really needs it, and I want it to cover multiple areas since he's almost always traveling. I am a little confused, and I just don't know where to start from. I've seen companies showing off medicare plans for the upcoming years, like this one
https://www.medisupps.com/medicare-supplement-plans/medicare-supplement-plans-2022/. Do you need to buy it in a specific period of time and its term is one year or more?