if you haven't finished your return online you'll need the desktop app for which you'll have to pay to finish.
full PC or Mac. you'll have to also upload the .tax2021 file if you started it.
https://turbotax.intuit.com/personal-taxes/past-years-products
you can no longer e-file so you'll have to print and mail. make sure to follow the filing instructions. when you mail it you should use either proof of delivery or tracking service.
