For the Economic Impact Payments (stimulus) that were issued during 2020, you have until May 17, 2024 to file a tax return for the Recovery Rebate Credit.
For the Economic Impact Payment (stimulus) that was issued in 2021 you have until April 15, 2025 to file a tax return for the Recovery Rebate Credit.
To complete and file a 2020 and 2021 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 2020 and 2021 tax return can only be printed and mailed, they cannot be e-filed using TurboTax.
Use a separate envelope when for each tax year being mailed. You should also use a tracking service available from the US Post Office so that you will have proof the tax returns were received by the IRS.