If you download or have a pdf file you can open it with any pdf reader program. If you download the .tax file like .tax2023, .tax2022 etc. you need that year’s Desktop program installed to open it. But you can’t install 2020 or prior programs anymore. They only support and update the last 3 years.
Or are you asking about importing prior year 1099 forms into Turbo Tax? You can’t import prior year documents. You will have to manually enter them.
