Free Online Tool to Add Page Numbers to a PDF
Documents that started life without page numbers — exported reports, scanned booklets, combined PDFs — are much easier to navigate and reference once numbered. LovePDFImg's Page Numbers tool adds a number to every page of your PDF, with control over where it appears, what format it uses, and which number it starts from.
Numbers are drawn directly onto each page using your browser's JavaScript engine, so the original content stays exactly as it was, just with a number layered in the position you choose. As with all core tools here, everything happens locally — your file is never uploaded to a server.