Final answer:
Stephen can use the keyboard shortcut Alt + F9 to toggle between data and field codes in Microsoft Word. This is useful for viewing the raw field codes or the results of those codes in a Word document.
Step-by-step explanation:
The keyboard shortcut that Stephen can use to toggle between data and field codes in Microsoft Word is Alt + F9. When working with fields in Word documents, such as those used in mail merge or for inserting dates or page numbers, toggling can be quite helpful. By pressing this keyboard combination, Stephen can switch between seeing the actual field code and the result of the field code. For example, toggling a date field code would show either something like "{ DATE \at the rate of "MMMM d, yyyy" }" or the actual current date, depending on whether the field code or its result is currently displayed.