How PDF Watermarking Works
AnyTool adds text watermarks to PDFs by drawing text with configurable font size, color, opacity, position, and rotation onto each page using pdf-lib. The watermark is embedded directly into the PDF page content stream.
How to add a watermark to a PDF?
Upload your PDF, type your watermark text, customize font size, color, position, opacity, and rotation, then click Apply. The watermarked PDF downloads instantly — processed entirely in your browser.