iBooks Author: Add an accessibility description to an object
You can add an accessibility description to any floating or anchored object in your book (but not to inline objects). When the book is viewed on iPhone, iPad, or Mac, VoiceOver (the Apple screen reader) reads the object’s accessibility description aloud.
If you don’t provide a description, VoiceOver reads the object’s default description (“pie chart,” for example).
VoiceOver automatically reads object titles, labels, and captions.
Add or edit accessibility text
Select an object.
In the Accessibility Description field, do any of the following:
Add accessibility text: Enter the object’s descriptive text and press Return.
Edit accessibility text: Select the existing text, enter the new descriptive text, and press Return.
Remove accessibility text: Select the descriptive text and press Delete.