1. Start with Document Structure

Ensuring the document's structure is set up properly is essential for accessibility. This involves making sure that the document uses proper headings, lists, and tagging.

• Headings: Make sure headings are properly tagged with heading styles (H1, H2, H3, etc.) rather than just bold or larger font sizes. Use tools like Adobe Acrobat's "Tags" panel to verify.
• Lists: Check if lists are marked with proper list tags, not just manually indented items.
• Reading Order: Confirm that the document’s reading order follows a logical flow. You can check this in Adobe Acrobat by going to the "Read Out Loud" function and verifying that the text is read in a logical order.
• Use of Tags: The PDF should be properly tagged for screen readers. You can check tags by opening the document in Adobe Acrobat, going to "View" > "Show/Hide" > "Navigation Panes" > "Tags."

2. Use Accessible Fonts and Colors

Make sure text is easy to read for people with low vision.

• Fonts: Use clear, simple fonts such as Arial or Helvetica. Avoid decorative fonts that may be hard to read.
• Contrast: Ensure there is sufficient contrast between the text and background. A ratio of at least 4.5:1 for regular text and 3:1 for larger text is recommended by WCAG guidelines.
• Text Size: Ensure that the font size is large enough for comfortable reading. A minimum of 12 pt is recommended for body text.

3. Alternative Text for Images

Provide alternative (alt) text descriptions for all non-decorative images, charts, and graphics.

• Images: Check that all meaningful images have a descriptive alt text. This can be done in Accessibility Panel under “Add alternate text”
• Charts and Graphs: Ensure that data in charts or graphs are described in the text or via an alternative description (e.g., a table or a textual summary).

4. Check Links and Navigation

Accessible PDFs must provide clear, easy navigation, especially for users with disabilities.

• Links: Ensure all links are descriptive and convey their purpose (e.g., “Click here” is not accessible).
• Table of Contents: If applicable, a Table of Contents should be created using bookmarks and should link to the appropriate sections.
• Bookmarks: Verify that the bookmarks are well-structured and correspond to the document’s headings for quick navigation.

5. Forms and Interactive Elements

Forms should be accessible, so users with assistive technology can fill them out.

• Form Fields: Ensure form fields (e.g., text fields, checkboxes, radio buttons) are properly tagged and labeled.
• Instructions: Provide clear instructions for filling out forms, including error messages.

6. Tables

Tables should be properly structured and accessible.

• Headers: Make sure the table headers are marked properly using the <th> tag, and ensure that headers span the correct rows/columns.
• Data Cells: Data cells should be tagged with <td> and appropriately related to headers.
• Avoid Nested Tables: Keep tables simple. Nested tables can cause issues for screen readers.

7. Check for Document Properties

Verify that the PDF’s document properties are filled out and accurate.

• Title: The document title should be set and should describe the content of the document.
• Language: The document’s primary language should be set. This ensures that screen readers can read the document in the correct language.

8. Verify PDF Accessibility with Tools

Use various accessibility checking tools to confirm the document is accessible.

• Adobe Acrobat Pro: Use the built-in accessibility checker in Adobe Acrobat Pro. Go to "Tools" > "Accessibility" > "Full Check."