How to Make a PDF Accessible (ADA/WCAG Compliance)

Here's something that doesn't get talked about enough: most PDFs are completely inaccessible to people who use screen readers. Like, not partially broken — totally unusable. A screen reader hits your average PDF and gets back something like "image image image image." Super helpful, right?

PDF accessibility isn't just a nice-to-have anymore. If you run a business, work in government, or publish anything that the public interacts with, there's a real chance you're legally required to make your PDFs accessible. The ADA, Section 508, WCAG 2.1 — these aren't suggestions. They're standards, and courts have been enforcing them.

But let's skip the fear-mongering. The real reason to care about accessible PDFs is simpler: about 15% of the world's population has some form of disability. That's over a billion people. If your documents don't work for them, you're not just non-compliant. You're leaving people out.

What "Accessible PDF" Actually Means

An accessible PDF is one that works with assistive technology. That's the short version. The longer version involves a few specific things:

Tagged structure. This is the big one. A tagged PDF has an underlying structure that tells screen readers what's a heading, what's a paragraph, what's a list, and what order to read things in. Without tags, a screen reader just sees a flat dump of text — or worse, nothing at all if the PDF is a scanned image.

Alt text on images. Every image, chart, or graphic needs a text description. If a sighted person gets information from looking at it, a non-sighted person needs that same information delivered differently.

Logical reading order. PDFs don't always store content in the order you see it on screen. A two-column layout might have the text stored left column first, then right column — or it might interleave them randomly. Accessible PDFs define the correct reading sequence explicitly.

Proper language declaration. The document needs to declare what language it's written in. Screen readers use this to pick the right pronunciation engine. A French document tagged as English sounds like a disaster.

Navigable headings and bookmarks. Just like a web page, your PDF should have a heading hierarchy that people can use to jump around the document. Nobody wants to listen to a 40-page PDF read start to finish just to find section 7.

The Difference Between ADA, Section 508, and WCAG

These get mixed up constantly, so let's sort them out.

WCAG (Web Content Accessibility Guidelines) is the technical standard. It's published by the W3C and defines specific success criteria at three levels: A, AA, and AAA. Most legal requirements point to WCAG 2.1 Level AA as the target. It covers everything from color contrast to keyboard navigation to — yes — document accessibility.

ADA (Americans with Disabilities Act) is US law. It requires that places of "public accommodation" be accessible, and courts have increasingly interpreted that to include websites and digital documents. The ADA doesn't spell out exact technical requirements, but when courts need a benchmark, they usually point to WCAG 2.1 AA.

Section 508 applies specifically to US federal agencies and organizations that receive federal funding. It was updated in 2017 to align directly with WCAG 2.0 AA. If you do business with the government, this is your world.

In practice, the target is the same for all three: WCAG 2.1 Level AA. Hit that, and you're covered under pretty much any legal framework that might apply to you.

How to Check If Your PDF Is Accessible

Before you fix anything, you need to know where you stand. Here's how to check:

Use a screen reader yourself. On Mac, turn on VoiceOver (Command + F5) and try to navigate your PDF. On Windows, NVDA is free. Spend five minutes listening to your document being read aloud. You'll immediately understand what's broken. This is the single best test because it's the actual user experience.

Run an automated checker. Adobe Acrobat Pro has a built-in accessibility checker (Tools → Accessibility → Full Check). It catches the obvious stuff — missing tags, missing alt text, undefined language. It won't catch everything, but it's a solid starting point.

Check the tag structure. In Acrobat, open the Tags panel (View → Show/Hide → Navigation Panes → Tags). If you see a structured tree of Headings, Paragraphs, and Lists — good. If you see nothing or just a flat mess — that's your problem.

Making an Existing PDF Accessible

Got a PDF that fails every check? Here's the practical workflow.

Step 1: Add Tags

If your PDF has no tags at all, you need to add them. In Acrobat Pro, go to Accessibility → Add Tags to Document. The auto-tagger does a decent job on simple layouts but struggles with complex ones. For anything with multiple columns, tables, or mixed content, you'll need to manually fix the tag structure after auto-tagging.

If you're starting from a Word or Google Docs file, the better move is to go back to the source and fix things there. Word's built-in heading styles (Heading 1, Heading 2, etc.) translate directly into PDF tags when you export. Using styles properly in your source document is the single highest-impact thing you can do.

Step 2: Add Alt Text to Every Image

Go through each image in the document and add descriptive alt text. In Acrobat, right-click the image in the Tags panel, choose Properties, and fill in the "Alternate Text" field.

Good alt text describes what the image communicates, not just what it looks like. "Bar chart showing Q3 revenue up 23% over Q2" is useful. "Chart" is not. "Blue and gray bar chart with company logo" is somewhere in between but misses the point.

If an image is purely decorative — a border, a background pattern, something that carries zero informational value — mark it as an artifact so screen readers skip it entirely.

Step 3: Fix the Reading Order

Open the Order panel in Acrobat and walk through the document page by page. The content should flow in the order a person would naturally read it. Headers before body text. Captions near their images. Sidebars marked appropriately.

This is tedious on long documents. There's no way around that. But it's also where a lot of the real accessibility value lives.

Step 4: Set the Document Language

Document Properties → Advanced → Reading Options → Language. Pick the right one. Takes two seconds and fixes a whole class of screen reader pronunciation issues.

Step 5: Make Tables Accessible

Tables are accessibility kryptonite. Every data table needs header cells marked as headers (TH tags, not TD). Complex tables with merged cells or multiple header rows need scope attributes. If you have a table that's being used for layout rather than data, it should be marked as a layout table or restructured entirely.

Honestly, if your table is really complex, consider whether it needs to be a table at all. Sometimes a well-structured list communicates the same information more accessibly.

Step 6: Check Color Contrast

WCAG requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text. If you've got light gray text on a white background — which, let's be honest, way too many designers love — that's a fail. Use a contrast checker tool to verify.

Building Accessible PDFs from the Start

Retrofitting accessibility is painful. It's always easier to build it in from the beginning.

If you're creating documents in Word, Google Docs, or any other editor before exporting to PDF, these habits make the difference:

Use heading styles consistently. Don't just make text bigger and bold — actually apply Heading 1, Heading 2, etc. This creates the tag structure automatically.

Add alt text to images before exporting. Both Word and Google Docs let you right-click an image and add alt text. Do it when you insert the image, not after.

Use actual lists, not manual bullet points. Typing a dash and a space doesn't create a semantic list. Use the list formatting tool so the structure is preserved in the PDF.

Don't use color alone to convey meaning. "Items in red are overdue" doesn't work if someone can't see red. Add a text label or icon too.

Keep your layout simple when possible. Single-column layouts are inherently more accessible than multi-column ones. If you need columns, use your editor's column feature rather than text boxes.

Using OnlyDocs for Accessible PDF Editing

If you need to make quick edits to a PDF while keeping it accessible, OnlyDocs lets you edit PDFs directly in your browser. You can add text, annotations, and form fields without stripping out the existing tag structure.

For teams that regularly produce PDFs, having an online tool that doesn't require installing Acrobat on every machine saves both money and headaches. You can make edits, add signatures, fill forms, and export — all from the browser.

The Bottom Line

PDF accessibility isn't rocket science, but it does require attention. The biggest barrier isn't technical difficulty — it's awareness. Most people creating PDFs have never thought about whether a screen reader can parse their document. Now you have.

Start with your most public-facing documents. Your website downloads, your customer-facing forms, your published reports. Get those right first. Then work backward through your archive as time allows.

Perfect accessibility on every document overnight isn't realistic. But "we're working on it and making progress" is a defensible position. "We never thought about it" isn't — not anymore.