Xiaomi 12
Android 12.0
1 Find "Data roaming"
Press Settings.
Press SIM cards & mobile networks.
Press Advanced settings.
Press Data roaming.
2 Turn data roaming on or off
Press the drop down list next to "International roaming".
Press the required setting to turn the function on or off.
3 Return to the home screen
Press the Home key to return to the home screen.