Password protect and redact important documents, and optimize file size with compression.

One hand holding a stack of papers with a lock on them signifying password protected files being handed to another outstretched hand

Acrobat’s Protect and Optimize PDF tools provide precise control over your content while allowing viewers access across multiple platforms. A variety of basic and advanced settings offer you highly customized protection to keep your content secure.

Password security settings dialog box showing options for permissions and for changing the scope of encryption

Protect your file with passwords

Manage access to your PDF documents with confidence. Control who can open, view, and print your content. You can even control what resolution they can print. This is extremely useful when sending proofs to a client for final approval while maintaining copyright of the original artwork. In addition to password-protecting the PDF, you can also limit search engine access by encrypting the document metadata as well.

  1. Open a PDF in Acrobat.
  2. Select Protect from the menu on the right.
  3. In the Protect banner above the document window, click Protect Using Password.
  4. Type in your password and save it in a safe location because password recovery is not available.
  5. If required, click the Advanced Options menu and choose Encrypt with Password or Encrypt with Certificate.
  6. If you select the advanced encryption options, you’ll need to choose the level of protection you desire by checking one or both of the following boxes: Require a password to open the document, or Restrict editing and printing of the document. The latter includes options to restrict the copying of text and images, or deny screen reader devices access to the text.
  7. Choose your software Compatibility level.
  8. Choose which type of content you wish to encrypt and click OK.
PDF Icon being squeezed by a clamp signifying document compression

Optimize the file size of your PDF

As the name implies, a Portable Document Format, or PDF, is meant to be portable. Compressing your PDF without losing quality is extremely important. Whether the PDF is saved to the Document Cloud or you are planning to email it, smaller file sizes mean faster loading for your viewers across different device types. There are three ways to compress the file size of your PDF, but which option should you choose?

Reduce File Size is a common choice when you are looking for basic optimization. Unless you have an advanced understanding of the elements in your document, it is recommended that you typically use this option.

  1. Open a PDF in Acrobat.
  2. Click the Optimize PDF icon from the menu on the right. If you don’t see this option in the menu, scroll down and click More Tools to add the Optimize PDF option to the list of your tool choices. You can also add this option from the Tools menu at the top of the window.
  3. Click Reduce File Size in the toolbar.
  4. On a PC, set the version compatibility and click OK. On a Mac, the default will refer to the existing version.
  5. Choose a location to save your file and click Save. Keep the same file name to overwrite the current file, or use a new name for the file with the smaller PDF size. 
PDF Optimizer dialog box showing compression options for Image Settings, Grayscale Images and Monochrome Images

Advanced Optimization gives you the flexibility to be selective about what types of content you want to optimize and by how much. There are several extended options for images, fonts, transparency, and what items are discarded.

  1. Open a PDF in Acrobat.
  2. Open the Optimize PDF tool from the pane on the right.
  3. Click Advanced Optimization in the toolbar at the top and specify your compression needs, then click OK.
  4. Select a location to save your file and click Save. Keep the same file name to overwrite current file, or use a new name for the file with the smaller PDF size.

Optimize Scanned Pages is used only when you are working with a scanned document. This will allow you to perform text recognition while reducing the overall file size of the document.

Compressing PDF documents reduces file size while maintaining readability, but finding the best balance between file size and file integrity will be up to you and may vary in many cases. If you are sending a document to be printed, it is always a good idea to check with your vendor before compressing, and to use the settings they recommend.

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