If you are referring to the Health Insurance section of the program, you do not enter any type of Medicare supplemental policy in that section. What is being presented is a list of uncommon plans which you would not be using since you are on Medicare. Medicare is classified as "minimum essential coverage" under the Affordable Care Act (ACA). Just answer NO to the question concerning the uncommon plans and Continue. That will complete the Health Insurance section of the program.
Use the procedure I gave in the Answer above to report the premiums paid for the supplemental insurance.
