Where are you seeing that you are required to provide the 2018 tax return to the IRS?
Are you referring to the 2018 AGI? This number is used to electronically file your tax return. It can be found on the 2018 Form 1040 Line 7
https://ttlc.intuit.com/community/agi/help/how-do-i-find-last-year-s-agi/01/25947
To access your current or prior year tax returns sign onto the TurboTax website with the userID 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 View adjusted gross income (AGI)
Or go to this IRS website for free federal tax return transcripts - https://www.irs.gov/individuals/get-transcript
If your tax return continues to be rejected with the 2018 AGI then enter a 0 (zero) for the AGI and e-file again.
If this is also rejected then you will have to print and mail the tax return.
See this TurboTax support FAQ for printing a tax return for mailing - https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online...
