Using the Tools in the Tool Box > Using Annotations Tools
To delete annotations:
In Gallery view, double-click the annotated image to display it by itself.
Hold down the Shift key, and select the annotations to be deleted by clicking once on the text box and once on each arrow.
Right-click, and a shortcut menu is displayed.
Click Delete.
Note: To delete all of the annotations you made, open the Tool Box and click Undo All.