A "SAMPLE" watermark clearly marks preview or draft documents. Here is how to stamp it diagonally across every page for free.
Navigate to the watermark tool and upload your PDF.
In the text field, type "SAMPLE". Set rotation to 45 degrees for a diagonal stamp. Set color to gray or light red. Set opacity to 30–50%. Set font size to 80–120pt depending on page size.
Tip: Gray at 30% opacity is the professional standard for sample watermarks — clearly visible but not distracting from the content.
Click Apply to All Pages. The SAMPLE watermark appears diagonally across every page.
Once applied and saved, the watermark is embedded in the PDF. Keep the original unwatermarked version. Use pdfeditor.onl/remove-watermark-from-pdf to attempt removal from the watermarked version.
Yes — completely free at pdfeditor.onl/watermark-pdf.