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Tagged PDF

A key part of making PDFs accessible is ensuring the document is “tagged.”
A “tagged PDF” is a type of PDF that includes an underlying tag tree, similar to HTML, that defines the structure of the document. PDF tags make it possible to identify content as headings, lists, tables, etc., and to include alternate text for images. Without tags, none of these accessibility features are possible.

Unfortunately, not all PDFs are tagged, and many document authoring tools are not capable of creating them. Microsoft Word and PowerPoint, and Adobe InDesign, all export to tagged PDF. However, most other authoring tools do not, including Google Docs and Slides. To learn more about making accessible PDF's with the previously mentioned tools, see Exporting Accessible PDFs.

If PDFs are not tagged, tags can be added using Adobe Acrobat Pro. Additional training on adding tags to an untagged PDF, or remediation, is recommended.

Autotagging

Auto-tagging an untagged PDF document can have unpredictable results. Inspecting the tag tree after auto-tagging is recommended.

To add tags to an untagged document, follow these steps: select All tools > Prepare for accessibility > Automatically tag PDF. 

I Started Autotagging and the Progress Bar is Stuck at 20%!

In 2023 Adobe introduced cloud-based auto-tagging feature to enhance accessibility and generate detailed tags for eligible PDF documents, and since this is the standard setting for Adobe. When enabled, this feature relies on Adobe's cloud servers to process the accessibility tagging of the document. This method can sometimes fail if there are connectivity issues or disruptions in Adobe's cloud services, leading to the process stalling. If Acrobat determines the PDF is unsuitable for the new cloud-based auto-tagging, it should then pivot to tag the PDF locally using the existing tagging method.

Sometimes there are issues and Adobe is not able to make that pivot to locally tag the PDF. If your autotagging progress gets stalled at 20% cancel the process, select Menu > Preferences > Accessibility then uncheck the box labeled Enable cloud-based auto-tagging for accessibility. 

Example of Preference settings in Adobe Acrobat Pro. The Preferences menu and the Enable cloud-based auto-tagging for accessibility are highlighted with an orange rectangle.

This will enable for the file to be autotagged locally, but be aware that local tagging may not be as accurate as thorough as tagging done through Adobe's Cloud based service. Remember to run an accessibility report after tagging to correct any potential errors produced by the autotagging. 

For more details, see Enhance document accessibility with cloud-based auto-tagging.

Inspect the Tag Tree

To inspect the tag tree, follow these steps:

  1. Menu > View > Show/Hide > Side Panels > Accessibility Tags. This will display the tags in descending order from top to bottom.
  2. Review the tag tree of the PDF to ensure proper semantic structure and proper reading order. Tags may be modified manually, however making changes to the tag tree can have unpredictable results. Save often!

Using the Reading Order Tool

Adding tags to an untagged document using the Reading Order tool is part of a manual tagging or remediation process.
See Tab and Read Order in Documents for more details. 
For more information, see the Adobe Support documentation on using the Reading Order tool for PDFs.
Additional training on using the Reading Order tool to remediate a PDF document manually is recommended.

Tips for using the Reading Order tool

  • Save the document (or a copy of it) before you use the Reading Order tool, as undo-redo isn't supported for all operations. For more information, see Undo or redo the tag changes done using the Reading Order tool.
  • Choose Menu > View > Page display > Single-page view from the hamburger menu (View menu in macOS), when using the Reading Order tool.

To open the Reading Order tool you will select All tools > Prepare for Accessibility > Fix reading order. 

Once open you will be instructed to use your mouse to draw a rectangle around the content, and then you will click one of the buttons listed to apply the apropriate heading structure from the Reading Order dialogue box. 

Example of the Reading Order tool dialogue box in Adobe Acrobat Pro

It is important to note that while tags are essential for PDF accessibility, they do not guarantee accessibility. They must be used properly, as described throughout this website, in order for the PDF to be accessible.