Swipe up from the bottom of the screen and pause in the middle to open the app switcher
Swipe left or right to find the app you want to close
Swipe the app preview up off the screen to close it
On iPhone with a Home button, double-click the Home button to open the app switcher
Swipe left or right to find the app you want to close
Swipe the app preview up off the screen to close it