It will not help you to use the current online software to compare with a 2020 return. Online is only for 2021 returns and the tax laws and forms are different for 2021. If you enter 2020 income information into 2021 it will be all wrong. As already mentioned, if you want to compare the results of using TurboTax for a 2020 return, you would need to purchase and download the desktop software for 2020 to a full PC or Mac.
If you need to prepare a return for 2018, 2019 or 2020 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
https://turbotax.intuit.com/personal-taxes/past-years-products/
You may also want to explore purchasing the software from various retailers such as Amazon, Costco, Best Buy, Walmart, Sam’s, etc.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
