NOTE: Android is highly customizable and may look different depending on your manufacturer. The steps below may vary for different devices.
Method A: Using Quick Settings
A1) Swipe down from the top of the screen to open the Quick Settings window.
A2) If Power Saving mode is not visible, swipe down from the top of the screen to expand.
A3) Tap Power saving mode.
B1) Open the Settings app.
B2) Tap Battery and device care.
B3) Tap Battery.
B4) Tap the toggle to switch on Power saving mode.
The Android device will be in Power Saving mode.