向 PDF 添加水印 — 免费且私密 |易工具

How to Add a Watermark to a PDF

Drag and drop your PDF file or click to select it from your device. Your file stays in your browser — nothing is uploaded.

Enter your watermark text and adjust the opacity. The watermark will be applied diagonally across every page of your document.

Click "Apply" and download the PDF with your watermark. The original file remains unchanged.

Your files never leave your device. The watermark is applied in your browser using WebAssembly — no server uploads.

No registration, no file limits, no watermarks from us. Add your own watermarks to as many PDFs as you need.

The watermark is embedded directly into the PDF with a real font, ensuring it displays correctly on all readers and when printed.

Is my PDF uploaded to a server?

No. FyleTools processes everything directly in your browser using WebAssembly. Your file never leaves your device.

Can I customize the watermark appearance?

You can set the watermark text and opacity level. The watermark is applied diagonally across each page for maximum visibility.

Can the watermark be removed later?

The watermark is embedded into the PDF content. It cannot be easily removed by others, which is the point of watermarking documents for protection.

Does the watermark appear on all pages?

Yes. The watermark is applied to every page of the document automatically for consistent protection throughout.

Can I change the watermark font size?

The watermark size is automatically optimized for the page dimensions. Adjust the opacity to control visibility.

Is the watermark visible when printing?

Yes. The watermark is permanently embedded in the PDF content and will appear on printed copies.

Does this work on mobile devices?

Yes. The tool runs in your browser on any device. Add watermarks to your PDFs from your phone without installing any app.

Can I remove a watermark after applying it?

No. Watermarks are permanently embedded. Always keep your original un-watermarked file in case you need the clean version.