Ask the plumber to play customer, and export your bill as a PDF and determine if he has the same visual issue as you. Learn what version of Pages he is using, as that may also be revealing.
I don't believe there is anything you can do with the received Pages document that you have if the missing billing information issue persists when exported to PDF and that print panel selection we have discussed.
One wag might be to download and install the free, current LibreOffice Suite and open (read-only) the Pages document you received in it. If the visuals you need are there, export as a PDF. You won't see LibreOffice on the Finder Open With menu (for Pages documents), so you will need to launch LibreOffice and use its File menu to open the Pages document.
Be certain on that LO download page that you are careful to choose the version for your Mac hardware (e.g. macOS Intel, or macOS Apple Silicon). LibreOffice is an open source, Microsoft Office clone and has been in continuous development (by one name or another) since 1992.