What if I close the app before it sends?
The queue is written to the phone, not held in memory. It survives closing the app and restarting the phone, and sends on the next launch with signal.
From the guide Working offline.
Working offline
Both phone apps keep working when the signal does not. Fill in a form, log an expense, close a work order, take a meter reading, clock out — it is saved on the handset and sends itself the moment you are back on a network. You do not have to remember to do anything.
Read the whole guide: Working offline