PDFgear lets you check detailed information about a PDF file, edit document metadata, and view its security permissions.
Right-click anywhere on the PDF page and choose Document Properties from the menu.
Open the Document Properties
The Document Properties window has two tabs: Description and Security.
The Description tab shows general details about the PDF:
Edit the Metadata in PDF on Mac
To edit metadata: Type directly into the fields for Title, Author, Subject, or Keywords. Then click Done to save.
The Security tab shows what actions are allowed or blocked. It lists:
Check the PDF Security
If something is marked Not Allowed, you’ll need the password or the owner’s permission to change it.