Overview
PDF tags are invisible labels that tell screen readers what each piece of content actually is: a heading, a paragraph, a table, etc. Your document can look perfectly organized on screen and still be confusing for anyone using assistive technology, unless the tags underneath are set up correctly too.
Introduction to PDF Tags
Use the following video to familiarize yourself with the most common PDF tags and how they appear in Adobe Acrobat. The Accessibility Guy's blog post on PDF tag types serves as a helpful companion resource, providing the video along with a quick reference list and brief explanations of common PDF tags.
If you come across a tag that isn't listed in the video, use Common PDF Tags and Their Usage as a guide.
Helpful Hints when Reviewing PDFs
Document Tag
Every PDF tag tree starts with one tag: Document. It's the root. Every other tag in the file is nested underneath it. When you open the tags panel and see one tag wrapping everything else, that's it.
Headings
All headings should be nested and sequential. Watch How to create better (and more accessible) heading structures for a breakdown of heading hierarchies.
Lists
You won't always see an Lbl tag inside a list item, and that's okay. Including it gives a screen reader a cleaner way to announce the bullet or number, but its absence doesn't break the list. If Lbl is the only thing missing from an otherwise well-tagged list, it's not necessary to retag just to add it back in.
Table
Some tables also break the header and body into their own container tags: THead for the header row or rows, and TBody for the rest of the data. These aren't required, but when they're present, they sit between Table and the TR tags, grouping the header rows separately from the body rows so the structure of the table is even clearer. As long as the associated tags are correct, leave them as is.
Span
You may see these tags throughout the tags panel. Span tags simply signify that there is a font style change. You can typically ignore these tags in the panel.
Don’t Delete Tags Instead Artifact the Content
If you delete a tag outright, the content underneath it doesn't disappear, it just becomes untagged, which usually causes more accessibility problems than it solves. Instead, use the Reading Order tool to mark that content as an Artifact first. This tells assistive technology to skip it entirely, without leaving untagged content behind in your tag tree.
Only when a tag is completely empty (not even a blank content box is within the tag), can you delete it.
Resources
For more, review this additional resource:
Support
For support, email [email protected]