It is possible to amend a tax return prepared elsewhere using TurboTax but it will be a real pain. It would be much easier to use the software used originally to prepare the returns than to use TurboTax.
In order to use TT software, first you have to purchase the desktop software for that year and download it to a full PC or Mac. Then you have to re-create the tax return EXACTLY as it looked when sent to the IRS. You then tell the software you will file by mail in order to "trick" the software into thinking you filed. THEN, you use that same software to prepare a Form 1040X in order to amend the return, and print, sign and mail the Form 1040X to the IRS. It takes the IRS about 3-4 months to process an amended return. It is too late to receive a refund for an amended return for any year earlier than 2019.
To file a return for a prior tax year
If you need to prepare a return for a prior return 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/
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.
