State income tax that you actually paid in 2021 is an itemized deduction on your federal tax return (if you itemize your deductions). Taxes you actually paid include state withholding from your pay, plus any state tax payments. Turbotax gets the withholding from your W-2 automatically. To add the additional payment with your 2020 tax return, go to the Deductions page and look for "Estimates and other taxes paid."
