Get your taxes done using TurboTax

Go to this IRS website for the mailing address, by state, for a Form 1040-X - https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment

When mailing the amended tax return include the Form 1040-X, signed and dated.  Do not include the Form 1040 but only other forms and/or schedules that were changed by amending.

Additionally, how can you be using the TurboTax online editions to amend a 2021 tax return.  The information for amending a 2021 tax return on the TurboTax account website requires you to download the 2021 tax data file and then purchase one of the 2021 desktop editions to amend the 2021 return.