Medicare Supplement plans which are also known as Medigap cover what Original Medicare does not. It is a Medicare insurance product offered by private insurance companies and meant to cover the 20% gap in your healthcare cost including copayments, Part A and B deductibles, and coinsurance. Some Medicare Supplement plans offer additional coverage beyond what Medicare offers, such as fitness membership, worldwide travel emergency, hearing aids, and vision.
After your visit or procedure, your provider sends the bill to Medicare, then your Medigap plan covers out-of-pocket costs that you are responsible for after Medicare has paid their portion of your medical costs. You could have low to zero out-of-pocket costs, depending on what letter Medigap plan you choose.
Once you enroll in Medicare Part B, you will have a six-month window to enroll in Medigap insurance without having to answer health questions and go through medical underwriting. Once this window has passed, you can still enroll in a Medigap plan anytime, but you must pass medical underwriting.
No, they are not the same. You leave Original Medicare when you sign up for Part C, while Medigap/Medicare Supplement plans work with Original Medicare to provide you more comprehensive benefits than Original Medicare has to offer.