Go to Settings > Accessibility features > One-Handed mode , and enable One-Handed mode.

You can access One-Handed mode using any of the following methods:

• If you are using Gestures and Slide across bottom to switch apps is enabled, slide across the bottom of the screen and hold.

• If you are using Gestures and Slide across bottom to switch apps is disabled, slide across the bottom of the screen in an arc and hold.

• If you are using Three-key navigation, slide across the bottom of the screen.

• If you are using Gestures and there is no Slide across bottom to switch apps switch, slide across the bottom of the screen.

Touch any area outside the mini-screen view to exit.