In any case, you might be FAR better off going to a tax professional to prepare and file those past years of taxes. They aren't too busy this time of year.
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BUT IF you want to use TTX software:
1) The "Online" TTX software can only be used for 2022 tax preparation, and can only be used up to mid-October of 2023.
2) The TTX "Desktop" software can be purchased and used for 2019, 2020, 2021, and 2022. Only 2022 can be e-filed and the rest would have to be printed and mailed (separate envelopes) to the IRS, and separate ones to your state too if your state has an income tax. The Desktop software requires a full MAC or Windows computer....(and 2019 software may disappear from availability sometime later this year.)
TurboTax 2021 Prior Year Tax Prep - File Past Years' Taxes (intuit.com)
3) For years 2017 and 2018, you would have to go to the IRS website, download their PDF tax forms for those years, prepare them manually....then print and mail them in. (OR, use a local Professional tax person).
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
