Add Watermark
在浏览器中使用「Add Watermark」完成文字与文档相关任务；输入内容和结果默认在设备上处理。
使用步骤
如何使用
- Choose one local PDF up to 50 MB and enter a watermark of up to 120 basic Latin characters.
- Choose the position, opacity, rotation, font size, and color.
- Apply the watermark locally, review the page count and output size, then download the new PDF.
Local PDF editing
The selected file is read and rewritten entirely in this browser. No upload, account, or server storage is used. The watermark is drawn into the page content, so it appears in ordinary PDF viewers.
Supported documents and limits
This focused tool accepts one PDF up to 50 MB and 500 pages. Password-protected, encrypted, digitally signed, XFA, and malformed PDFs are rejected. Watermark text uses the built-in Helvetica font and supports basic Latin characters.
Output and privacy
Applying a watermark reserializes the PDF and may remove unsupported document features or metadata. Keep the original when you need signatures, forms, attachments, exact byte preservation, or an editable source.
常见问题
你可能还想知道
Is my PDF uploaded?
No. The file is opened, edited, and downloaded locally in this browser.
Can I watermark a signed or password-protected PDF?
No. Signed, encrypted, password-protected, and XFA PDFs are rejected so the tool does not silently invalidate or mis-handle them.
Will the watermark be selectable?
Yes. It is added as PDF text using the standard Helvetica font, although the chosen rotation and opacity affect how it looks.
Does the output preserve every PDF feature?
No. The document is reserialized by pdf-lib. Keep the original for signatures, forms, attachments, metadata, and features this focused editor does not preserve.