How can I upload tax documents to my FAFSA account for my daughters financial aid

You can save a PDF copy of your tax return and upload that elsewhere if that is what you mean. You will see an option to download a PDF copy of your tax return to your computer after you have completed your tax return and logged into your TurboTax account. You will see the option on your home page in TurboTax.

Instead of "pushing" your tax information into the FAFSA, you log into the FAFSA page and "pull" tax information from the IRS into your FAFSA.

See this link https://studentaid.gov/resources/irs-drt-text for more detailed instructions.