There is no place to enter on a federal tax return that you have Medicaid. The only thing anyone has to enter about health insurance is when they have a 1095A for marketplace health insurance---aka "Obamacare" aka Affordable Care Act, aka insurance from healthcare.gov. If you are on Medicaid, you do not get a 1095A. When it asks if you have a 1095A say NO and just move on.