If the home in which the camera is benefits from the Heads-Up subscription features, you can define Activity and Block zones for the camera.

Activity zones

Activity zones (up to 3) are the only zones that the camera will consider to detect motion. By default, the whole field of view is a single activity zone. 

Note that if you delete every activity zones, the camera will not detect any movement as a result, as it will not monitor movement anywhere. If you want the camera to monitor movement for the entirety of its field of view, have an activity zone cover the whole snapshot.

Block zone

Block zone (up to 1) is similar to a cut out in the field of view of the camera. It behaves as if this part of the view does not exist and is fully censored. This makes the zone not visible on any streaming or recording, and as a result, no motion can be detected from this zone.
By default the camera has no block zone defined.