How would I go about completing tax returns for past years please?

[DoninGA]

To complete and file a prior year (2022 thru 2020) tax return using TurboTax you would need to purchase, download and install on a personal computer one of the desktop editions for each tax year required from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/

A  prior year tax return can only be printed and mailed, it cannot be e-filed using TurboTax.

Use a separate envelope for each tax year when mailing the tax returns.