Alt text for images
Self-described Links
Unique Sheet Tab Names
Simple Tables with Identified Column and Row Headers
Users who are unable to see images depend on document authors to supplement their images with alternate text, which is often abbreviated as alt text. The purpose of alt text is to communicate the content of an image to people who can't see it. When a screen reader encounters an image with alt text, it announces the image and then reads the alt text.
If images are purely decorative and contain no informative content, they do not require a description. However, they may still require specific markup so screen readers know to skip them.
Alt text is also necessary for SmartArt graphics, shapes, charts and tables.
Screen readers provide users with the ability to scan a list of links. Without clear, meaningful hyperlink text, the user has no idea what a specific link is.
Screen readers read sheet names so the user can understand the contents of a workbook and easily navigate through it. Therefore all sheet tabs need to have unique names, and blank sheets must be removed as well.
Screen readers keep track of location in a table by counting table cells, as well as using header information to identify rows and columns. Without this information, the screen reader loses count and can't provide helpful information to the user. Tables with blank cells, merged or split cells, and a table nested in another also confuse the screen reader.
Excel has a built-in Accessibility Checker that can usually identify issues with any of the items listed above. To use the Accessibility Checker, click File > Info > Check for Issues > Check for Accessibility.
Inspection Results will appear to the right of your document and contain accessibility errors and warnings that must be fixed to make the document accessible. Why Fix and How to Fix information is also provided under the results.