If you mean that your Traditional 401(k) plan had non-deductible money in it and that was moved to a 401(k) Roth (Designated Roth), then you shroud have received a 1099-R with a code G in box 7, the amount moved in box 1, a zero amount in box 2a and the amount of non-deductible (after-tax) amount in box 5 to report it.
If last year then the 1099-R should have been sent to you no later than Jan 31, 2022.
If you meant something else then please explain more.
**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.**
