TurboTax will ask about your prior years "basis" which is the 2018 8606 line 14 value from the 8606 that should have been filed with your 2018 tax return.
You can file the 2018 8606 by itself and mail it in.
https://www.irs.gov/pub/irs-prior/f8606--2018.pdf
https://www.irs.gov/pub/irs-prior/i8606--2018.pdf
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
