Answer:
Live Preview.
Step-by-step explanation:
This is a feature specifically found in the microsoft power point in detailing or slides showing in a preliminary stage of its previews.
By default, when you select the composing email content and change its text format, such as text font, size, color and so on, the live preview will be displayed when you put your cursor on different text format.
Actually the live preview function can be enabled or disabled manually in Outlook. In this tutorial, we will show you how to enable or disable live preview in Outlook in details.