If you’re still rocking a Home button (like the iPhone SE or older models), you’re a legend. Just double-click the Home button. It’s the same button you use to go home, but twice, fast. The screen will slide up to show your app cards.
How to keep apps from disappearing from your iPhone by turning off app
Now, swipe left or right to find the app you want to evict. Then, swipe up on that app’s card to send it packing. It’s like flicking a playing card off a table—satisfyingly final.