The irs says that they didn't receive the 2018 they need proof they want me to efile it

A 2018 tax return cannot be e-filed using the personal editions of TurboTax.

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 Download/print return (PDF)

A 2018 tax return can only be printed and mailed, it cannot be e-filed.

Print, sign, date and mail the tax return to the IRS.  Include with the mailed return any forms W-2 and 1099 which have taxes withheld.  Go to this IRS website for mailing addresses - https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment

There are no penalties for filing a tax return after the due date if filing for a tax refund or there are no taxes owed.

you can not e-file a 2018 return using TT.  if it's absolutely necessary to e-file, you'll have to seek out the assistance of a professional.  if you used TT to prepare your 2018 return and it's complete, you can print and mail it in.  there will probably be fees.   if incomplete you'll need to buy the 2018 desktop software to complete it.  the .tax2018 online file can be uploaded so you can complete the return rather than starting from scratch 

If you owed on the 2018 return then look in the PDF for the filing history  and send the electronic postmark as the proof of successful filing. 

Your return's electronic filing status history records all e-filing activity related to the return, including the Electronic Postmark. You can print it out if needed. 

TurboTax Online

https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp  -- enter the Social Security number of the first taxpayer on the return and the ZIP code to retrieve your filing status history.