The TurboTax online editions are only for tax year 2019.
To complete prior tax years using TurboTax, 2016 thru 2018, you would need to purchase, download and install on a personal computer one of the desktop editions for each tax year you need to file from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/
Prior year tax returns can only be printed and mailed, they cannot be e-filed. Use a separate envelope for each tax year being mailed.
