2018? What do you mean when you say TT gave you all the necessary documents? What documents? TurboTax cannot get your 2018 W-2's, 1099's or any other documents for your 2018 return in 2020, so not sure what you think TurboTax "gave" you.
Online tax preparation for a 2018 return has been closed for over a year. In order to prepare and file a 2018 return you need to use desktop software on a full PC or Mac, and your return has to be printed, signed and mailed.
Online preparation and e-filing for any tax year prior to 2017 is permanently closed.
To file a return for a prior tax year
If you need to prepare a return for 2017, 2018 or 2019 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
https://turbotax.intuit.com/personal-taxes/past-years-products/
Remember to prepare your state return as well—if you live in a state that has a state income tax. The state return must be mailed in its own envelope to the state—-do not mail your state return to the IRS.
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.
https://ttlc.intuit.com/questions/1900990-how-do-i-file-a-prior-year-tax-return
Note: Desktop software requires a full PC or Mac—it cannot be installed to a mobile device
If you are getting a tax refund there is no penalty for filing after the deadline. If you owe tax due, the late penalties and interest will be calculated by the IRS (or state) after they receive your tax return and the payment for the tax due as shown on the tax form. You will receive a bill from the IRS/state for the penalties and interest owed. TurboTax will not calculate the penalty or interest.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
