Medicare Part B and D go under medical expenses as insurance premiums on a Schedule A (itemized deductions).
You have to itemize your deductions in order to deduct them.
Your question says you are using, TurboTax Free Edition. You cannot itemize on TurboTax Free. You would need to upgrade to Deluxe or higher.
Before you do that, you need to consider whether the premiums will make a difference.
Taxpayers get either a standard deduction or an itemized deduction. You only use itemized if it is higher than your standard. The standard depends on your filing status. It is $6350 (plus a little if you are over 65) and $12,700 if you are married.
Also, medical expenses are only deductible after they exceed 7.5% of your AGI. So depending on how much you paid, it may not enough to itemize.
If you do upgrade and itemize, you can enter then you enter them this way:
There are two places you can enter the Medicare premiums in TurboTax.
First, when you enter your SSA-1099 to report your social security benefits, you'll see entry boxes for the various Medicare types. When you enter your premiums on this page, TurboTax will automatically carry them to the itemized deduction section for inclusion with Medical Expenses.
You can also enter your Medicare premiums directly on the Medical Expense screens for itemized deductions -- along with any other qualified medical expenses -- by clicking on Federal Taxes, then Deductions & Credits, then scroll down to Medical and click on Medical Expenses. Follow the prompts and enter the premiums in the Medical Insurance Premiums box.
Use one entry area or the other, but not both. Otherwise, they'll wind up duplicated. [edited 4/6/17]
