We don't. You need to look at your 2018 1040 line 7.
If you don't have a copy, look in "Your tax returns and documents" near the bottom of the Tax Home screen for a copy if you used the same TurboTax account last year.
I have done this many times and it is not working .
I heard this claim when I first sent my original Tax for 2019 and I fixed it and sent in on . Then I got a notice from Turbo Tax that said it was not corrected. I have corrected five times. I have been trying to find out if IRS has accepted my first correction and has been refusing the last five. I have TRIED till I am blue in the face trying to find out if they accepted the original correction and are turning all the subsequent changes back. I WOULD LIKE TO KNOW HOW I CAN DO THIS I HAVE TRIED MANY TIMES AND THEY JUST TURN ME DOWN.
Maybe one went through so the rest are rejecting.
You can double check your efile status here
https://turbotax.intuit.com/tax-tools/efile-status-lookup/
If it's not Accepted I would give up and mail it.
How to mail a return from the Online version
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return. Don’t forget state.
Important! Mail Federal and State in separate envelopes and mail each year in separate envelopes.