A tax return cannot be used as proof of income.
The income you received in 2019 is reported on your W-2's and any Form 1099's that you received. Those are used for proof of income.
Print your tax return, sign and date the return. Give a copy of the tax return to whomever is requesting the tax return.
To access your current or prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Year and Click on Download/print return (PDF)
If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created. TurboTax does not store online any returns completed using the desktop editions.