lock PDF File Encryption and Hardening

Set advanced permission protection for PDF files, supporting preventing content modification, prohibiting annotation editing, restricting printing and format, blocking file concatenation, disabling content extraction and form filling, ensuring document security.

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PDF permission settings, PDF encryption tool, PDF anti-modification, PDF password security control

PDF Generation Settings

Restricts operations on the document after opening (not supported by all readers)

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Frequently Asked Questions (FAQ)

Yes, our online PDF Add Password Protection tool is free to use forever, no registration, subscription, or software download required. We are committed to providing efficient and convenient document security services.

We support two types of passwords:
  • Open Password: Requires a password to open the file.
  • Permission Password: Used to restrict operation permissions, can be applied even if the open password is not entered.
The following permission controls are also supported:
  • Prevent file content from being modified
  • Prevent adding or editing annotations
  • Prevent printing (can choose whether to allow low-resolution printing)
  • Prevent concatenation (merging/splitting) documents
  • Prevent content copying and extraction (e.g., text, images)
  • Prevent form filling

It will not affect normal reading, but certain operations (such as copying text, printing, editing, etc.) will be restricted. You can flexibly configure permission combinations as needed to balance security and usability.

Your file security is our top priority. All uploaded PDF files will beimmediately deleted from the serverafter the operation is completed. We do not store or access any of your personal data and document content. The entire operation process is encrypted to ensure your privacy and security.

Yes, our online tool isfully compatible with various devices and operating systems. Whether you use a computer, phone, or tablet, as long as you have an internet connection, you can easily set PDF password protection anytime, anywhere.

Password protection can be revoked, but you must reopen the document with the same permission password and change the settings. If you forget the permission password, you will no longer be able to modify or remove these restrictions, so please keep your password information safe.

This tool supports most standard PDF formats, including common types such as PDF/A, PDF/X, PDF/UA. As long as the file is not protected by DRM or special encryption, passwords and permissions can be set normally.