Your 401(k) would be reported by your employer in box 12 on your W-2 with a code "D". It does not get entered anywhere else.
If you mean a Designated Roth (a 401(k) Roth) that would also be in box 12 on your W-2 with a code "AA".
A personal Roth IRA in a bank would be on your bank statements and entered in the IRA contribution section.
**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.**