- Visit your Settings app

- Tap “Display & Brightness”

- Using the slider, move right to make your display brighter and left to make it more dull

Your iPhone can also determine what your screen’s brightness should be depending on the light around you using its custom ambient light sensor called True Tone. So, if you’d like your screen brightness to decide for you, follow these steps:

-Go to Settings

-Tap Display & Brightness

- Toggle ON True Tone