Help text works differently in PDF. In a pdf file the help text is a tooltip for the given field. In the pdf file if you hover your cursor over the field and wait 1 second, you will see the tooltip with your help text.
That is seriously a poor design. There's no visual indicator to the end-user that any type of help is available at all. Nice that help eventually pops up, but as someone who has to fill out the form, you wouldn't know that by looking at it.
The purpose of forms is to make the repetitive collection of information easy. Hiding help icons or any type of help indicator adds complexity and forces users to think. This should be "don't make me think" simple. This makes the simple complex.