You have to report receiving the second stimulus payment on your 2020 federal tax return, even if it was received in 2021.
The stimulus questions are asked in the Federal Review section of the TurboTax program. Any payment you were eligible to receive based on the 2020 Federal tax return but did not receive will be entered on the Federal tax return, Form 1040 Line 30 as a tax credit. The credit is included in the federal tax refund or it will reduce the amount of federal taxes owed.
