If you wish to put a watermark, like a "Draft Copy" or "Classified" label on your Pages document before printing or distributing a PDF, you can do it easily using Section Masters. You can place anything back there, such as text, shapes, or images. In this example, we'll place some diagonal text across the background and it will appear on all pages.
Want to know more about how to use Pages on your Mac? Check out this MacMost course!