You must enter the 2020 contribution in the IRA contribution interview that will but it on the 2020 8606 line 1.
You must have the 2019 8606 with the 2019 contribution on line 1,3 and 14.
When entering the 2020 1099-R:
You will be asked of you had and tracked non-deductible contributions - say yes. The enter the amount from the last filed 8606 form line 14 if it did not transfer. Then enter the total value of any Traditional, SEP and SIMPLE IRA accounts that existed on December 31, 2020.
That will produce a new 8606 form with the taxable amount calculated on lines 6-15 and the remaining carry-forward basis on line 14.
NOTE: If there is an * next to line 15 then 6-14 will be blank and the calculations will be on the "Taxable IRA Distributions worksheet instead.
**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.**
