Watermark PDF stamps text (like "CONFIDENTIAL" or "DRAFT") or a logo image onto every page of a PDF at once, useful for marking a document's status or ownership before sharing it.
Every page, at the same position and settings. There's currently no option to watermark only a subset of pages.
Yes. The watermark is drawn as a new layer on top of each page's existing content, regardless of whether that page is real text or a scanned image.
No. It's watermarked entirely in your browser, using the same local PDF library as this site's other PDF tools. Nothing is sent to a server.