While Medicare Supplements are standardized by the federal government, each state can set its own guidelines about which Medicare supplement plans must be used by all providers to all age groups, and which plans might be used at the insurance provider's discretion. This implies that some Medigap plans are more popular than others, and if you have an interest in a less-common plan, you may require to do a little digging or seek advice from an representative to discover providers who offer the plan you have an interest in.

https://mymedicaresupplementplan.org/compare-medicare-supplement-plans/