Not user of PS, so won't be able to give you an exact response.

That'd be just the same as municipal bonds interest, except it's coming from discounted bonds.  If these are private activity bonds, you'd have a number in Box 9 that would be added back as a TPI on F.6251 (which most people won't care these days).

If your client is subject to state tax, you'd need to look at the supplemental info to determine the out of state portion that would be subject to tax in each state.

I use google, such as:

proseries 1099-int

https://proconnect.intuit.com/support/en-us/help-article/form-1099-int/entering-form-1099-int-proser...

double click on the line where you entered the interest to select the option.