Marking a PDF as CONFIDENTIAL protects sensitive documents from unauthorized sharing and clearly communicates the document's status. Here is how to add a professional CONFIDENTIAL watermark to any PDF in seconds.
Visit the watermark tool in any browser — no account or installation needed.
Upload your PDF. Type CONFIDENTIAL in the watermark text field. Set the font size to 60–80pt. Set rotation to 45°. Set opacity to 35–40%. Choose red for maximum visual impact.
Tip: A 45° diagonal rotation at 35% opacity is the international standard for CONFIDENTIAL document stamps.
Click Apply to All Pages. The CONFIDENTIAL watermark is embedded into every page. Download the result.
The current tool applies the same watermark to all pages. For per-page watermarks, apply one at a time using PDF Studio.
The watermark is flattened into the PDF page content. Standard PDF viewers cannot remove it.
Yes — completely free at pdfeditor.onl/watermark-pdf.