Tracking is a feature that allows you to continuously share your location in real time with your monitoring team, when needed.
If it is switched on (via Settings) then your location is updated and shared periodically using the Tracking Update Interval found in the Settings.
This is one of the features that consumes a noticeable amount of battery power. This is because your phone has to use its Location Services as well as its wifi or mobile antennas in order to send your location in real time. If you are concerned about excessive battery consumption, you can coordinate with your monitoring team to use Tracking only when needed.