I'm not sure why my suggestion about PDF Xchange viewer is not being considered.

I just now opened a PDF document with some images and text, and typed "added to document" at the bottom of one page, then saved it AS A COPY to be sure, and then REopened it with another PDF viewer, and the added text was right there. This seems like all the original request asked for.
"All I want to do is simply add some text notes at the bottom of the page. The music takes up less than half a page, so there is plenty of room. "