You have until April 15, 2020 to file your 2019 federal income tax return. If you had a Marketplace plan in 2019 and used advance payments of the premium tax credit (APTC) to lower your monthly payment, you’ll have to "reconcile" your tax return.
Through “reconciling,” you’ll find out if there's any difference between the premium tax credit you used and the amount you qualify for. Any difference between the two figures will affect your refund or tax owed.
How to "reconcile" your premium tax credit on 2019 taxes: