It is recommended to read the following article as an introduction to the subject-
What is a History Record and when is it created?
The history record gets uploaded from the Control Unit through the Mobile App to the Cloud (Web App) if there is Bluetooth and Internet connection and one of the following conditions is met:
Every fifth iteration of the synchronization between the mobile and the Control Unit.
When enabling the "Collect Data" button in the Data Management tab of the Mobile App (Click here for instructions).
If you do not have Internet access, the history records will be saved on the Mobile until you have Internet access. Then they will synchronize to the Cloud.