For past year tax returns, you can only use the CD version of the software that you purchase, download and install on your Windows or MAC computer. Start with the oldest year first. TurboTax only supports their software for the current tax filing season and 3 years back. So you can only use the TurboTax software for a 2019 tax return and newer. To get prior year TurboTax programs go to https://turbotax.intuit.com/personal-taxes/past-years-products/ and make sure you select the link for the tax year you need.
Note that a prior year tax return can not be e-filed. The IRS says so. You will have to print, sign and mail the return to the IRS. The same will hold true for your state also, if your state taxes personal income and you are required to file a state tax return.
