Movement through a web page or application should follow a logical order that matches the visual order of content on the page.
For most documents, screen readers read from left to right and top to bottom. When creating documents, be aware of this and author content accordingly. For documents that contain content in multiple columns, be sure to test with a screen reader.
PDF files present unique challenges since they are generated from other software products that may not export content in a logical order for reading. Techniques for testing and, if necessary fixing, the read order in PDFs depends on whether the PDF is a document or form.
Techniques for PDF documents
In Adobe Acrobat Pro, select All Tools > Prepare forAccessibility > Fix Reading Order.
In the Reading Order window, make sure “Show page content groups” and “Page content order” are selected. This feature provides a visual indication of the approximate order in which content will appear if automatically re-purposed for display on a small screen.
For more information, see the Adobe Support documentation on using the Reading Order tool for PDFs. Additional training on using the Reading Order tool to remediate a PDF document manually is recommended.
Generally, this order is fairly consistent with the read order for screen readers. However, a more accurate test for screen reader order is to check the tag tree. To do this select Menu > View > Show/Hide > Side Panels > Accessibility Tags.
With both of these features in Acrobat Pro, you can modify the read order if items are out of sequence.
In Reading Order, click the “Show Order Panel” button, then drag the various blocks of content into a logical reading order.
The process is the same in the Tag Tree: If the tags are not in the visual order (left to right, top to bottom) or not in a logical order needed for context, simply drag them to their appropriate place in the tree. As you drag the tag over the Tags Panel a black line will appear in places you can drop the tag. Be careful to drop the tag under the correct tag. This action can take some practice.
Techniques for PDF forms
To test an interactive PDF form, open the form in any desktop PDF reader and move through the form fields by pressing the Tab key. Fields will be highlighted as they receive focus.
If fields are not arranged in the expected sequence, this can be fixed in Adobe Acrobat Pro. Go to All Tools > Prepare a Form.
All form fields will be listed in tab order in a sidebar panel. Simply drag fields to their correct position in the tab order.