Default margins, paper size, and other differences in both capability and configuration can make a document appear very differently when viewed or printed on one system as compared to another. When Word displays a document in a print layout or page view, it uses the characteristics of the currently-selected printer to determine what the document will look like when printed.
Word processors like Word are generally designed to produce documents to be printed. In a nutshell: it’s all about the printer. Your client is on the right track: that’s exactly what PDF is for. They were never meant to distribute documents to others for reading.
Word documents were never intended to do what you’re doing.
