Check Accessibility problems as you work in Word, Excel and PowerPoint
Now you can see on the status bar if there’s accessibility problems as you work with your Word, Excel or Powerpoint documents.
Tucked away on the Accessibility Pane is a option to run the accessibility checker as you work, instead of only on request.

Keep accessibility checker running while I work
Turning this on doesn’t seem to affect Word’s performance. It appears to be a background process that runs when Word is otherwise idle, much like the Grammar checks.
This is a global Word setting, not for each document. That’s a nuisance because there are documents where accessibility is a concern but not always. In our view it really should be a per-document setting … oh well.
Status Bar Accessibility notices
Turning “Keep accessibility checker running while I work” on, adds an accessibility: notice on the Status Bar.
Accessibility: Good to go
“Accessibility: Good to go” is Microsoft’s code for no accessibility issues found.

Accessibility: Investigate
“Accessibility: Investigate”, Microsoft’s euphemism for accessibility problems found in the document, sheet or deck.
Either way, clicking on the Accessibility part of the status bar opens the Accessibility Pane.
Fixing common Office document accessibility problems
How to use Excel’s Accessibility Ribbon