@joshuapeters1922 A general rule of thumb to help guide you is that the return consists of the Form 1040 plus any forms and schedules that have an "Attachment Sequence Number" in the top right corner. Occasionally, but less commonly, someone may have additionally prepared an optional "supporting statement" to go with a form.
You said "past year's taxes." If you are referring to an Online return prior to 2020, then at this point in time you only have one choice of PDF available at the Tax Home for a prior-year return, which is most often the large one as @DanPaul02 mentioned above.
For future reference, however, you can plan ahead when you save your current 2020 return for your records. For your current 2020 return, you have a choice of PDFs that you can get by opening the return and going to the Print Center. We can tell you how to do that. At the Print Center you can choose from
"Just my tax returns", or "include government worksheets (optional)", or "include government and TurboTax worksheets (optional.)"
You would need to do this before the October 2021 online shutdown, since after that point in time only the large PDF is available.
I usually save 2 PDFs for my records: a PDF with the return "as filed" and the largest PDF with all of the TurboTax and government worksheets. It's also possible to save the tax data file, if you wish. But see the following caution:
NOTE: Remember all PDF tax documents and tax data files are very sensitive files, since they contain your personal ID info, financial data, and possibly bank account numbers, etc. Be sure to store them safely and securely to guard against computer theft, hacking, etc.
