The issuer of the 1099-R enters that on the form if this is a 1099-R for a designated Roth and the box 7 code indicated a designated Roth (code B or H). Enter what the form you received has or blank of no entry on your 1099-R.
**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.**