You can add page numbers on Google Docs to any document. All you need to do is go into a document's Insert menu, which will give you several options.

You can add page numbers to your Google Docs document from either the web or mobile app. Here's how to use the web app to add page numbers: Open your Google Docs file. Go to Insert on the menu bar ...

Sure, Google Docs lets you add headers and footers to documents, but within those headers and footers you can't include dynamic information like page numbers.