How to make a PDF accessible
Tag the structure, set reading order and alt text so assistive tech can read it.
Author with real structure
Use true headings, lists and table styles in the source (Word/InDesign), not manual formatting. Structure exported from a well-styled source becomes the PDF tag tree.
Add the tag tree
Export as a tagged PDF (InDesign: "Create Tagged PDF"; Word: check accessibility settings). An untagged PDF cannot be read in order by assistive tech.
Set reading order and alt text
In Acrobat’s Reading Order / Tags panel, confirm the order matches the visual flow and give every informative image alt text (mark decorative images as artifacts).
Check contrast and language
Ensure text meets the WCAG contrast ratio and set the document language so screen readers pronounce it correctly.
See where it actually stands
Preflight reports untagged pages, reading-order issues and contrast as pass / fail / not-evaluated — an untagged PDF is reported not-evaluated, never a false "accessible".
FAQ
What makes a PDF accessible?
A tag tree with correct reading order, real headings/lists/tables, alt text on informative images, sufficient contrast, and a set document language.
Can a tool fully guarantee accessibility?
No automated tool can — meaningful alt text and logical reading order need human judgment. A checker flags machine-detectable failures and, honestly, what it can’t verify.