Note that you claim the deduction or credit on your 2021 tax return. You do not amend your 2020 tax return.
Under the new tax law that was passed in 2017, for repayments in 2018 through 2025, if the amount that you repaid is $3,000 or less you do not get any adjustment of the tax. Some states might allow a deduction or credit on the state tax return.
