iPhone 12
My phone uses a large amount of mobile data
Solution 2 of 6: Your phone is set to high data usage
You can control how much data your phone uses for different functions such as download and playback of high quality content, app updates and more.
Press Settings.
Press Mobile Service.
Press Mobile Data Options.
Press Data Mode.
Press the required setting.
Slide your finger upwards starting from the bottom of the screen to return to the home screen.