Lance- PAF 4.04.18 prints to file in RTF format. It appears that RTF commands inserted in the notes are not filtered out, and thus underlining could be used in Notes for reports printed to a Text Editor such as MSWord. (The report Preview or direct printing will then show both the RTF commands and the notes to be modified.)
I am not going to post the underlining, bold, italic,etc. commands here, but suggest that if you truly want to underline notes, you download the RTF spec from the Microsoft Site. If you use WordPerfect, the Spec may not open properly (gotcha). In that case, run the spec through WordPad.
Caution: You can really screw up your reports if you don't do RTF right. On the other hand it is simple to do it right. Gedcoms to other programs may cause havoc.