This is called “callout”. I typed the term into the Videohive search box and got those:
This particular item has a video tutorial that shows you how to make the point or the line of a callout element track/follow the object you want in your scene. Keep in mind this is an After Effects template, so if you don’t have After Effects you won’t be able to use this particular item at all.
Callouts. Thanks so much. Big big help!