PDF accessibility and SEO: alt text, tagged structure and compliance

PDF accessibility and SEO are deeply interconnected. The same structural elements that make a PDF accessible to screen readers also make it readable by search engines: heading tags, alt text on images, tagged content structure, reading order, and language specification. Google has increasingly favoured accessible content in rankings, and the technical requirements of WCAG 2.1 compliance align almost perfectly with what Google needs to understand and rank PDF content. This lesson covers how to create PDFs that are both accessible and SEO-optimised for hosting on your Wix site, including how to audit and remediate existing documents.

How Accessibility Improves PDF SEO

• Tagged headings give Google structural understanding of the document hierarchy
• Image alt text provides Google with context about visual content within the PDF
• Reading order ensures Google processes content in the intended sequence
• Language tags help Google understand and correctly index multilingual content
• Table headers help Google extract and understand tabular data
• Bookmark structure creates a navigable outline that Google can use

Creating Accessible PDFs from Word Documents

Make an accessible, SEO-friendly PDF from Microsoft Word

• Step 1: Use heading styles (Heading 1, 2, 3) consistently throughout the document. Never use bold text as a visual heading without the heading style applied.
• Step 2: Add alt text to every image. Right-click the image > Edit Alt Text. Describe what the image shows in 1-2 sentences.
• Step 3: Use Word built-in table formatting for tables. Ensure the first row is marked as a Header Row.
• Step 4: Use Word built-in list styles for bulleted and numbered lists instead of manual dashes or numbers.
• Step 5: Set the document language: File > Options > Language. This ensures the PDF carries the correct language tag.
• Step 6: Run the Word Accessibility Checker: Review > Check Accessibility. Fix all errors and warnings.
• Step 7: Add descriptive hyperlink text. Use "Download our pricing guide" not "click here" for links.
• Step 8: Export to PDF: File > Save As > PDF. Check "Create bookmarks using Headings" and "Document structure tags for accessibility".
• Step 9: Verify the PDF accessibility using the free PAC tool (PDF Accessibility Checker).
• Step 10: Upload the accessible PDF to your Wix Media Manager.

OCR for Scanned Documents: Getting Text Into the PDF

Scanned PDFs have no text layer, making them invisible to both search engines and screen readers. OCR (Optical Character Recognition) adds a text layer by recognising the characters in the scanned image. Adobe Acrobat Pro provides the highest-quality OCR with the "Recognise Text" feature, producing selectable text that closely matches the original. Free alternatives include Google Drive (upload a PDF, right-click, open with Google Docs to trigger OCR), Adobe Scan mobile app, and OnlineOCR.net. After OCR, always verify accuracy by reading through the document, as OCR can misread unusual fonts, handwriting, or degraded scans.

Fixing Existing PDFs for Accessibility

If you have existing PDFs without accessibility tags, you have two options: recreate them from the source document with proper formatting, or retroactively add tags using Adobe Acrobat Pro. Recreating is almost always faster and produces better results. However, for complex documents where the source file is unavailable, Acrobat Pro auto-tagging feature can add basic structural tags. After auto-tagging, manually review the tag tree in Acrobat Pro to fix any misidentified elements: check that all headings use the correct tag level, all images have alt text in the tag properties, and reading order follows the visual flow of the document.

Testing PDF Accessibility and SEO Readiness

Before uploading any PDF to your Wix site, run it through two checks. First, use the free PAC (PDF Accessibility Checker) tool from the PDF Association, which tests against PDF/UA standards and produces a detailed error report by category. Second, verify basic SEO readiness by opening the document in Google Chrome and using Ctrl+F to search for your target keywords. If the search finds the text, Google can read it. Check that headings are visually distinct and logically structured. Open File > Properties in Adobe Acrobat Reader and verify the Title, Author, and Subject fields are populated with keyword-rich content.

Colour Contrast and Font Legibility in PDFs

Colour contrast affects both accessibility compliance and user experience. WCAG AA standard requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text. PDFs with light grey text on white backgrounds, or coloured text on tinted backgrounds, frequently fail this requirement. Use a free contrast checker like WebAIM Contrast Checker to verify your text and background colour combinations before finalising your PDF. Font size should be minimum 10pt for body text and 12pt for optimal legibility. Avoid condensed or decorative fonts that reduce readability at small sizes, as these also reduce OCR accuracy.

Complete How-To Guide: Auditing and Fixing PDF Accessibility Across Your Wix Site

Full accessibility audit for all PDFs on your site

• Step 1: List every PDF on your Wix site from your earlier audit spreadsheet.
• Step 2: For each PDF, check: is text selectable? Are headings properly tagged? Do images have alt text? Is the reading order logical?
• Step 3: Use the free PAC (PDF Accessibility Checker) tool on each PDF. Record the number of errors and warnings.
• Step 4: Prioritise fixes: PDFs with the most organic traffic should be fixed first.
• Step 5: For each priority PDF, locate the source document (Word, Google Docs, InDesign). Apply proper heading styles, alt text, table headers, and list formatting.
• Step 6: Re-export to PDF with accessibility tags enabled.
• Step 7: Verify the new PDF passes the PAC accessibility checker with zero errors.
• Step 8: Replace the old PDF on Wix with the accessible version. Ensure the URL remains the same to preserve any existing search rankings.
• Step 9: For PDFs where the source document is lost, consider recreating the document from scratch if it receives significant organic traffic.
• Step 10: Establish a PDF creation standard: all new PDFs must pass the PAC accessibility checker before uploading to Wix.