An accessible, or tagged, PDF carries a hidden structural layer (headings, paragraphs, lists, tables and reading order) that is separate from its visual layout, along with alt text on images and correctly labeled form fields. Without these tags, a PDF that looks perfectly normal on screen can be unreadable to a screen reader, which sees only an unstructured wall of text or, in scanned documents, no text at all.
PDF accessibility is a distinct discipline from web accessibility, with its own tools and standards (PDF/UA), and it is one of the most common gaps organizations discover once they start auditing beyond their website, since PDFs published years ago were often never checked at all.
What Is a Tagged PDF?
A tagged PDF is a PDF file that contains a tag tree: an ordered, hidden outline that says what each piece of content is. One tag marks the document title as a heading, others mark a paragraph, a list, a table header cell or an image with its alt text. Screen readers such as NVDA, JAWS and VoiceOver read this tag tree rather than the visual page, so the tags decide whether a blind reader hears a well-organized report or a jumble of words in the wrong order. Tags also let text reflow on small screens and help search engines and AI tools understand how a document is structured.
Tagging is part of the PDF specification (ISO 32000) and is required by PDF/UA (ISO 14289), the international standard for universally accessible PDF. A PDF can be tagged and still be inaccessible if the tags are wrong, so tagging is the starting point, not proof that a file is accessible.
What Are PDF Tags? Common Tags and What They Do
PDF tags work much like HTML elements. These are the tags you will see most often in the Tags panel of Adobe Acrobat Pro, based on the Section508.gov guide to common PDF tags and their usage:
| PDF tag | What it marks | What to check |
|---|---|---|
Document |
The root of the tag tree; every other tag sits inside it | All real content is in the tree and nothing important is left untagged |
H1 to H6 |
Headings, from the document title down to subheadings | Levels follow the visual outline and do not skip, so users can jump between sections |
P |
Paragraphs of body text | Text reads in the right order and is not split into fragments |
L, LI, Lbl, LBody |
Lists, list items, the bullet or number, and the item text | Bulleted and numbered lists are real lists, so screen readers announce how many items they hold |
Table, TR, TH, TD |
Tables, rows, header cells and data cells | Header cells are tagged TH with the right scope, so each value is read with its row and column headers |
Figure |
Images, charts, logos and illustrations | Each meaningful figure has alt text that gives its purpose or key data |
Link |
Hyperlinks and cross-references | Link text makes sense on its own and every link can be reached with a keyboard |
Form |
Fillable fields, checkboxes and signature fields | Every field has a name (tooltip) that tells users what to enter |
| Artifact | Decorative content such as page numbers, running headers and borders | Repeated or decorative items are hidden from screen readers instead of being read on every page |
How PDF Tagging Works
PDF tagging is the work of adding and correcting tags so the structure matches what a sighted reader sees on the page. It happens in one of two places:
- In the source file. The cleanest tagged PDFs start in Word, InDesign or PowerPoint. Use real heading styles, the built-in list and table tools, alt text on images and a document title, then export with tagging turned on (in Word, the “Document structure tags for accessibility” option). Fixing the source template means every future export comes out tagged.
- In the PDF itself. When the source file is lost or the PDF came from a scanner, the PDF is remediated in a tool such as Adobe Acrobat Pro. Automatic tagging gives a first draft, then a person corrects the tag types, reading order, table headers, alt text, form field names, document title and document language.
Scanned PDFs are only pictures of pages, so they need optical character recognition (OCR) first to turn the image into real text, as the W3C technique PDF7: performing OCR on a scanned PDF describes. Other W3C PDF techniques cover heading tags, table tags, alt text on figures, artifacts for decorative images and setting the document language. For the hands-on remediation steps, see accessible PDF tagging.
How To Check If a PDF Is Tagged
- Check the document properties. In Adobe Acrobat or Acrobat Reader, open the document properties. The Description tab shows “Tagged PDF: Yes” or “Tagged PDF: No”.
- Open the Tags panel. In Acrobat Pro, the Tags panel shows the tag tree. Compare it with the page: headings should be H tags, lists L tags and tables Table tags, in the order a reader would follow.
- Run a checker. The free PDF Accessibility Checker (PAC) 2026 tests a file against PDF/UA (ISO 14289) and WCAG 2.2 Level AA. veraPDF is an open source validator that covers PDF/UA and can check files in bulk. Acrobat Pro also has a built-in accessibility checker.
- Listen to it. Read the file with the free NVDA screen reader. Move by heading, read a table cell by cell and tab through the form fields. Checkers cannot tell whether alt text is accurate or the reading order makes sense, so a person has to check.
“Tagged PDF: Yes” only means a tag tree exists. Many auto-tagged files still have paragraphs tagged as headings, tables with no header cells or charts with no alt text.
Tagged PDF vs Accessible PDF
Tagging is necessary but not enough on its own. An accessible PDF also needs:
- the right tags in a logical reading order
- alt text that describes each meaningful image or chart
- a document title and language set in the file
- enough color contrast (4.5:1 for normal text under WCAG Level AA)
- labeled form fields that work with a keyboard
- bookmarks so readers can move through long documents
PDF/UA sets the technical rules for how the file is built, while WCAG sets the outcome for readers. Most organizations test PDFs against both: WCAG 2.1 or 2.2 Level AA to meet the law, and PDF/UA to confirm the file structure.
Do PDFs Have To Be Tagged By Law?
Laws rarely use the word “tagged”, but the standards they rely on cannot be met by an untagged PDF.
- Section 508 (US federal agencies): electronic content, including PDFs, must meet WCAG 2.0 Level A and AA under E205.4 of the Revised 508 Standards, and authoring tools that export PDF must be able to export PDF/UA-1 files (504.2.2).
- ADA Title II (US state and local governments): the Department of Justice rule requires WCAG 2.1 Level AA for web content and mobile apps, including documents posted online. An interim final rule published April 20, 2026 moved the compliance dates to April 26, 2027 for entities serving 50,000 or more people and April 26, 2028 for smaller entities and special district governments. Some older documents are exempt, but not ones people still use to apply for or access services.
- Europe: EN 301 549 clause 10 applies WCAG-based requirements to non-web documents, and the European Accessibility Act has applied to many consumer products and services since June 28, 2025.
This is general information, not legal advice. Our document accessibility testing guide covers the rules for PDFs, Word and PowerPoint files in more detail.
Get Your PDFs Tagged and Tested
HalfAccessible’s IAAP-certified team has 10+ years of accessibility experience. We tag and repair PDFs by hand, fix Word and InDesign templates so future exports come out tagged, and test every file with PAC and NVDA before we hand it back. Our PDF remediation services are quoted per document set after a free needs assessment. If the PDFs sit on a website that also needs checking, start with a $500 Quick Audit or compare all pricing plans. Not sure where to begin? Book a $100 consultation with a specialist.