My 1st thought was to sent them the thing in *.DOC, have them fill in the blanks and do a Print-to-document thru one of the many Output-as-PDF printer drivers,
...then I thought about **why PDF?** I'm thinking you want the *data* portions to be easily edited but NOT the *boilerplate*--so you don't have to go back over the whole thing with a fine-toothed comb. Yes?? I don't use Adobe's PDF-creation app, but I'm assuming this can be done with *locked layers*
--but **they** need to have the writer app to do this (and one assumes the proper VERSION).
PDF editing sounds like a quagmire.
ISTM this is something to do thru a Web page e.g. Javascript.