TurboTax cannot mail or email your tax return to you. If you only need the 2017 AGI then follow this procedure -
To access your prior year online tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/
Scroll down and on the section Your tax returns & documents click on Show. Click on the Year and Click on View adjusted gross income (AGI)