PDF accessibility is one of the most overlooked aspects of document creation. When a PDF is inaccessible, it creates significant barriers for people who use screen readers, have low vision, have cognitive disabilities, or rely on keyboard navigation rather than a mouse. Making your PDFs accessible is not just good practice — in many professional and institutional contexts, it is a legal requirement. This guide explains the basics of PDF accessibility and practical steps you can take to create more inclusive documents.
What is PDF Accessibility?
An accessible PDF is one that can be used effectively by people with a wide range of abilities and disabilities. This includes people who are blind or have low vision and use screen reader software, people with motor disabilities who navigate using only a keyboard, people with cognitive disabilities who benefit from clear structure and plain language, and people with hearing impairments for whom audio in PDFs must have text alternatives.
An inaccessible PDF — such as a scanned image of a document — looks like a normal PDF but is essentially invisible to assistive technologies. Screen readers cannot read the text, and keyboard users cannot navigate through it.
The Difference Between Tagged and Untagged PDFs
The most fundamental accessibility distinction in PDFs is whether the file is tagged or untagged.
Tagged PDFs contain a hidden structure that describes the document's organisation — headings, paragraphs, lists, tables, images, and their reading order. Screen readers use these tags to present the content meaningfully. Microsoft Word, when used correctly, produces tagged PDFs when you export using File → Save As → PDF.
Untagged PDFs have no structural information. Screen readers cannot determine the reading order of the content, and the output for visually impaired users can be garbled or completely unintelligible. Scanned documents are always untagged.
Practical Steps to Create More Accessible PDFs
1. Use Headings Properly in Your Source Document
Before converting to PDF, structure your Word document using real heading styles (Heading 1, Heading 2, Heading 3) from the Styles panel — not just text that looks like a heading because it is bold and large. When exported to PDF, these headings become the structural tags that screen readers navigate.
2. Add Alternative Text to Images
Every meaningful image in your document should have alternative text (alt text) that describes its content. In Word, right-click an image → Edit Alt Text. Decorative images should have empty alt text to tell screen readers to skip them.
3. Use Real Lists, Not Manual Formatting
Bullet points created using the List button in Word are tagged as lists in the exported PDF. Bullet points created by typing a hyphen manually are just text — screen readers will read them as such, losing the context that they are a list.
4. Ensure Sufficient Colour Contrast
Text must have sufficient contrast against its background for people with low vision or colour blindness to read it. The Web Content Accessibility Guidelines (WCAG) recommend a minimum contrast ratio of 4.5:1 for normal text. Dark text on a light background is the safest approach.
5. Use Plain Language
Accessibility is not only a technical concern. Documents written in clear, plain language are more accessible to people with cognitive disabilities, people reading in a second language, and frankly, everyone. Short sentences, common words, and clear structure improve comprehension for all readers.
6. Avoid Scanned Documents When Possible
Scanned PDFs are images — they cannot be read by screen readers or searched by text. When you need to digitise a paper document, use OCR (Optical Character Recognition) software to convert it to searchable, selectable text rather than leaving it as a scanned image.
Why Accessibility Also Helps Everyone
Many accessibility features benefit all users, not just those with disabilities. Properly tagged PDFs are searchable, copy-paste friendly, and render correctly on all devices including small screens and e-readers. Adding alt text helps search engines understand images. Using real headings makes it easier to navigate long documents. Clear language helps all readers understand content faster.
Accessible documents are, in almost every way, better documents. The effort required to make a document accessible is small — and the benefit to readers is significant.