The applications that are installed on the phone, using them and updating them, consume the included internet.

The "Data usage" option allows you to check which of the applications you use consume the most internet for each phone model.

In case you use a WiFi connection, when the signal of the WiFi connection is weak, the internet traffic will be transferred via mobile data and the corresponding tariff model will be charged, so it is always good to turn off mobile data on the phone itself when using WiFi.

We recommend that the option for Tethering (mobile data sharing, hotspot) be turned off if it is not used.

It is also recommended that you always turn off the automatic update of the phone's operating system until you are connected to WiFi.