If you recharactorized it all and indicated that the recharactorized Traditional IRA contribution was to be non-deductible and that was on your 2018 tax return, the there should be 8606 forms with the non-deductible amount on lines 1,3 and 14.
Why do you think you need to amend 2018?
You would enter the 2019 1099-R for the conversion and enter the past years basis (line 14 from the 2018 8606) and the 2019 year end aggregate value of all IRA accounts and the taxable amount will be calculated on a new 8606 lines 6-18.
**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.**
