Reachability is a feature first introduced with the large 5.5-inch displays of the iPhone 6 Plus and has been used in all Plus-sized iPhones ever since. It was designed to help users reach buttons at the top of the display with one hand without over-stretching or awkwardly rearranging the device.
Though the iPhone X is considerably smaller than those devices, it still has a pretty big display. Depending on the size of your hands and how you hold your device, you might find it difficult to reach the top of the screen. Luckily, reachability is still an option – though it works a little differently now, and on iPhone X it’s disabled by default.
To activate this feature, open the Settings app and navigate to General > Accessibility. Scroll down and toggle the Reachability switch to the on position.
Then, to reach the top of the display you swipe down on the bottom edge of the display. This will move the content of the app halfway down the screen so it can be easily reached with your thumb while holding the device normally. Tap any button and the view will return to normal. Note that if you start your swipe too high Reachability won’t activate at all.