How to lock a pdf from editing without adobe acrobat?

How to lock a PDF from editing? Libre Office is a completely free, open-source office suite. If you already have it installed, you can use it to export any PDF with editing restrictions.

1. Open your PDF file using Libre Office. The program will automatically open it in the Draw application.

2. Go to the File menu, hover over Export, and then select Export as PDF...[citation:4].

3. In the dialog box that appears, click on the Security tab.

4. Click the Set Passwords button.

5. Here, you can set two different passwords:

Password to open: This prevents someone from even viewing the file.

Password to allow editing: This is the key for your goal. You can set a password to restrict permissions like printing, copying content, or modifying the document itself. A user can open the file without a password but cannot edit it without this second password.

6. After setting the password, click OK and then Export to save the locked PDF.

Since your main goal is to find a free solution about how to lock a PDF from editing, Libre Office is technically a free option. However, given the confirmed bug that allows easy bypass and the inherent weakness of PDF permissions, this method should be used with caution. It may not reliably "lock" your PDF from editing as you expect.