As efficient as your iPhone is, it does not hurt to completely close running apps from time to time, freeing up disk space and keeping background processes to a minimum. Forced shutdown is also a great way to troubleshoot bad apps and can often fix minor issues without having to restart the device.
This is identical on older iPhones since iOS 7: Press the Home button twice and swipe up on the problem app to completely kill it. This method does not apply to the iPhone 11, 11 Pro, and 11 Pro Max because they do not have a Home button. So you have to get used to new gestures that come with closing apps.
If you come from an iPhone X or X S the process of forced closing apps is the same. If you're new to the world of "notched" iPhones, find out how it works.
Force closing apps
Before you can force an app, you must first look at . App switcher. So, swipe up from the bottom of the screen and stop when your finger reaches the middle and pause until the app cards pop up. This break is crucial. If you move your fingers up quickly without stopping, you will return to the Home screen.
If you're in the app toggle button, swipe away until you find the destination app, then swipe up with the app card power it on. Repeat this process for any other app you want to close, then swipe from bottom to top to return to the Home screen.