page break function for entire pages?

Thanks. I don’t think so.
My site has some pages that would run 15+ pages if prepared on a word processor. As viewed on screen, these are presented as continuous and so are hard to work with for a reader.
I was hoping I could find some plugin or command which would break up such long files all at once into screen sizes the size of standard 8.5 x 11 wordprocessor pages or some equally workable size.
I know I can manually enter page breaks one at a time, but I was wondering whether there was some way of having a plugin to exercise a command like: “Insert equal page breaks the size of standard typing paper in the whole document all at once.” I’d want this also to respect image boundaries, but those I could re-adjust afterwards manually.
I thought there may be a way of setting up page formats before the page is laid down. I don’t know how I’d do this. But I’m also hoping there might be a way of applying such a regular page-break format after the page has been published.