If you had a non-deductible 2018 contribution and another non-deducible 2019 contribution then you must amend 2018 and 2019 and file the 8606 for each year.
If you actually did a Roth conversion in 2019 can reported it as a non-taxable rollover your amended 2019 must also correctly report that.
**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.**
