Free Online PDF Protection Tool

Add one AES-256 opening password, watermarks, or page numbers. Watermarks and page numbers are processed locally; password encryption uses temporary server processing.

Drop PDF here or click to open

Supports PDF files up to 100MB

Protection Features

One AES-256 opening password
Custom text watermarks
Image watermark overlay
Page number insertion
Watermark position control
Batch apply to all pages

How to Use

1

Upload Your PDF

Drag and drop or click to select your PDF file.

2

Set Protection

Choose one opening password, configure watermarks, or set up page numbers.

3

Download Protected PDF

Download and verify the result before sharing.

Frequently Asked Questions

Is PDF Protection Tool really free?+

Yes. OnePDFs is free to use, requires no account, and does not add an extra OnePDFs branding watermark; watermark tools add only the watermark you choose.

Is my PDF file safe and private?+

Watermarks and page numbers are applied locally in your browser. Password encryption sends the PDF and password over HTTPS; its temporary output is deleted after the response finishes, while interrupted leftovers enter periodic cleanup after the one-hour retention window. A browser copy can remain in this site's IndexedDB until you clear site data or the browser evicts it.

What file size limit does PDF Protection Tool support?+

The tool supports PDFs up to 100MB. Browser-local actions depend mainly on the document and your device; processing-service actions also depend on network transfer and service availability.

Do I need to install any software to use PDF Protection Tool?+

No installation is needed. Some actions run locally in your browser, while the privacy answer above identifies actions that use HTTPS upload and their server-retention policy.

Ready to Get Started?

Most operations are processed locally. Your files are handled securely.