Adobe PDF

Scanned documents that become PDFs are not accessible; they are treated like images by a screen reader. PDFs must be made accessible when they are created, through the use of tags. PDF tags provide a hidden, structured and textual representation of the PDF content that is presented to screen readers. The tags exist for accessibility purposes only and have no visible effect on the PDF file.

For example, screen reader users have very limited page access. They will not be able to navigate a page to locate a desired section of content unless the content creator has authored pages following certain markup guidelines and best practices. To convert a Word document to a PDF that is accessible, the Word document must be properly formatted before conversion or the PDF will likely not be accessible.

If possible, start with an accessible source document (e.g. in Microsoft Word) and export to an accessible PDF. However, if the original source document is not available, accessibility features can be added to the PDF using Adobe Acrobat Pro.