Changing text box size for complete document
I am editing a book and it is almost complete with textboxes exactly matching the page margins. I have set page numbers and headers in the parent page and that is fine. However I now see that the top of the text frame is a bit too close to the page number/headers. So I want to lower the top of the frame a bit. But it is a 200 page book and I don't want to have to do this on every page. Is there a way of selecting all the text frames so I can do this for the entire document? I have spent some time researching Google/YouTube but I have yet to find a solution.

