Please do one of the following steps: Securing PDF files with passwords, Adobe Reader Sep 10, 2022 — Access your PDF files in Finder with Acrobat Reader or Finder The latest Adobe applications (reader and acrobat) support PDF security. For more information, see the Adobe PDF Security blog article. Password protecting PDF files with Acrobat Use Acrobat, to open PDFs in Acrobat Reader. Download Acrobat Reader and install the latest version. For example, if you use Mac OS X 10.6 Snow Leopard, download Acrobat 9 from apple.com. Open Acrobat Reader and install the latest version. To do this, choose File > Library > Adobe Acrobat, and then click Acrobat → Update… in the toolbar in the top right corner. You should see the new Acrobat 10 (or higher) installation. Follow the instructions to install Acrobat 11 or higher. When you open a document with the default layout, you see a toolbar at the top of the window. A lock appears if Preview is running. Note: In version 9, a check appeared inside the “Lock PDFs (Windows)” button, but that is no longer the case after version 9.4. How to protect your PDF files with Acrobat Reader and Security Policy provides detailed information about a PDF and allows you to block specific content when editing the file (see a PDF). Open the PDF in Acrobat and do one of the following. If you are prompted by the Acrobat security dialog box, Do one of the following: Securing PDF files with Acrobat Reader and Security Policy Use Acrobat, to open PDFs in Acrobat Readers. To see Acrobat Reader and Acrobat Security Policy, click on the following links: Acrobat Reader: Acrobat Security & Control Panel. Adobe Acrobat and Acrobat Reader: How to secure PDF files using Acrobat Reader. How to secure PDF files with Open Document Format (ODF) Use OpenDocument Format (ODF) with PDF files to: Lock a PDF file to keep sensitive information secure The open document format (ODF) or Open Document Format or ODF file type allows you to write and open document files.