@sonjalmcdanel There should have been two links to download the tax return in the Your tax returns & documents section.
The first would have been this link Download/print return (PDF)
The second would have been this link Download .tax file
Based on your post you selected the Download .tax file which can only be opened by the TurboTax software for the year of the data file.
You need to select Download/print return (PDF) which can be opened by any compatible PDF viewer, such as Adobe Reader
