The difference between "offline" and "signed off" is the amount of time you will be away from the app.
Online - You are ready and willing to accept and complete trips.
Offline - You are stepping away from your phone but expect to be coming back to it shortly. Going to the restroom, getting gas, grabbing lunch.
Signed Off- You do not expect to be taking any more trips for the day.
If you plan on signing off for the day, please be sure to go "offline" first, and then "sign out" of the app. This way you do not continue to receive trips while you are trying to sign out. It also allows data from your trips to be sent to our systems.