How to Close Apps on the iPhone XS and iPhone XR
You’ve been closing apps on the iPhone the same way for ages — just press the home button. Same thing with force quitting apps: you simply double tap the Home button, then swipe up on the app you wanted to close.
Previously, if you wanted to close an app on your iPhone X running iOS 11, you had to long press on the app preview in the Recent Apps view, then swipe up to dismiss it. With iOS 12, you can simply swipe up from the moment you're in Recent Apps.
How to Close an App on iPhone X
1. Put your finger toward the bottom of the display and swipe up.
The app will close and you’ll return to the home screen.
How to Force Quit Apps on the iPhone X
1. Swipe up from the bottom of the screen and hold your finger on the display for about a half second. You’ll see the App Switcher appear with your apps laid out like a deck of cards stacked from left to right.
3. Swipe up on the app you want to force quit. In iOS 11 powered devices, you will have to press and hold on a preview and then either swipe up or press a minus button. iOS 12 has ditched the minus button as well, so all closing is done through swipes.