Designate a Portion of a 401(k) to a Roth

I have an account that is mostly in a regular 401(k), but a portion is in a Roth 401(k). How do I tell the program that a portion of the account is in a Roth?

You can designate the portion of a 401(k) plan that is in a Roth 401(k) as seen in the screenshot below.

 

related articles