I beleive the help text for pdf forms is shown when you mouse over the field. We are using the built-in mechanism within Reader/PDF to show help (not the question mark icon)
I have the same problem as kathyt1234. Unfortunately nothing shows up when I mouse over the field. Might there be another reason/solution for the problem?
@yvenabuc Are you using Adobe Acrobat or Adobe Reader to view and fill out the PDF?