Use the Add Markup 
tools to draw arrows, circles, ellipses, and freehand drawings in the viewing area.
When you save the markup, a snapshot 
is automatically created that includes your markup 
. Snapshots with markup are private in your model file. However, you can easily share this information with others by adding the snapshot with your markup to a story. All collaborators with access to the story can see your markup and respond with their own comments.
