Select Settings > Device > Display.

Brightness level

Sets the display brightness level on your device.

Dark theme

Enables or disables the dark color theme.

Wallpaper

Sets the wallpaper background on your device.

Screen timeout

Allows you to set the amount of idle time before your device turns off the display while using battery power.

Font size

Increases or decreases the font size on your device.

Auto-rotate screen

Enables the screen to rotate automatically between portrait and landscape display modes based on the device orientation or remain in the current orientation.