Captions and PDFsMaking PDFs, documents, video and audio work for everyone
Chapters (8)
  1. Why PDFs, documents and media need their own care
  2. Making a PDF accessible with tags, reading order and bookmarks
  3. Building Word files that turn into good PDFs
  4. Slide decks that turn into good PDFs
  5. Captions, subtitles and transcripts: what's the difference?
  6. When does a video need audio description?
  7. How to check a PDF for accessibility problems
  8. How to check a video or podcast for accessibility

Making a PDF accessible with tags, reading order and bookmarks

Last reviewed

Quick take

  • Tags tell software what each part of a PDF is.
  • The easy way to get good tags is to fix the source file, then export.
  • Complex pages may still need a repair tool afterward.
  • Bookmarks let readers jump to a section. They come from your headings.

What tags do

A tag is a hidden label inside a PDF. One tag says "heading". Another says "paragraph". Another says "table". Together they form an outline of the page that a screen reader can follow.

Tags are not the only thing that matters, but without them a screen reader has little to go on. Microsoft puts it this way: tags help people who use screen readers and other assistive technologies read and navigate a document.[1]

A tree. The top box is Document. Under it are Heading 1, Paragraph, Table and Figure. Under Table are Header cell and Data cell.
Tags give a PDF a hidden outline.

Start in the program that made the file

You rarely build tags by hand. You make them when you save or export. The best plan is to get the file right first, then export it with tags on.

The simplest way to get a correct reading order, says the W3C, is to structure the document properly. Do it in the program you write in, before you convert.[2]

Four numbered steps. One, write with styles. Two, run the accessibility checker. Three, save as PDF with the tags option on. Four, check the PDF.
Fix the source file first, then export, then check the PDF.

In Microsoft 365, the Save As box for PDFs has an Options button. Inside it, make sure the box called "Document structure tags for accessibility" is ticked.[1] In other programs, check the export options for a tagging setting. The wording differs from program to program.

Reading order

The reading order is the order in which a screen reader reads the page. In a PDF it comes mainly from the order of the tags, not from where things sit on the page.[2]

Picture a page with a side note beside the main text. The side note might sit in the middle visually. But if its tag comes last, the reader hears it last.

A page sketch with four blocks. The title is read first, the main text second, the side note third and the footnote fourth, even though the side note sits to the left of the main text.
Tag order sets the reading order. It can differ from where things sit.

Simple pages usually come out right. Busy pages are the risk. Pages with pictures, tables, footnotes, side bars or form fields may not convert in the right order.[2] Then the order has to be fixed in a repair tool such as Adobe Acrobat Pro.[2]

Headings

A PDF needs real heading tags, just like a Word file needs real heading styles. The W3C describes how headings in a PDF are marked so that assistive technology can recognize them.[3] If you used heading styles in the source file, the export normally carries them over.

Bookmarks

Bookmarks are a clickable outline in the side panel of a PDF reader. The W3C says they help people find content in long documents. That means those over a few pages, or with many parts.[4]

You don't type them one by one. If you add a table of contents in Word and then convert, its entries link to your headings. The headings then show up as bookmarks in Acrobat's navigation pane.[4]

A PDF page on the left with grey lines, an arrow labelled headings, and a Bookmarks panel on the right listing Introduction, Findings with Costs and Timing under it, and Next steps.
Headings can become bookmarks that let readers jump around.

For a one-page flyer, bookmarks add little. For a long report, they save readers a lot of scrolling.

Ready to build the source file? Go to Word files that convert well.

Sources

  1. Create accessible PDFs, Microsoft Support (accessed 2026-11-10)
  2. PDF3: Ensuring correct tab and reading order in PDF documents, W3C Web Accessibility Initiative (accessed 2026-11-10)
  3. PDF9: Providing headings by marking content with heading tags in PDF documents, W3C Web Accessibility Initiative (accessed 2026-11-10)
  4. PDF2: Creating bookmarks in PDF documents, W3C Web Accessibility Initiative (accessed 2026-11-10)