Samsung Galaxy S21 5G
Android 11.0
1 Find "Power saving mode"
Slide two fingers downwards starting from the top of the screen.
Press the settings icon.
Press Battery and device care.
Press Battery.
Press Power saving mode.
2 Extend the battery life
Press the indicators next to the required settings.
Press the indicator below "Power saving mode" at the top of the screen to turn on the function.
3 Return to the home screen
Press the Home key to return to the home screen.