Quitting all active applications is another way to free up some space on your phone's internal storage. Multiple apps running in the background might cause your smartphone to slow down since each of these apps uses memory space for each process request. As a result, the more programmes running in the background, the more storage space they consume, slowing down the speed of your smartphone. Even if you haven't used the applications in a while, they continue to operate in the background and are loaded onto your iPhone's memory until you do. Start the Multitasking view by double-tapping the Home button to rule out this as a possible reason. This will bring up a screen with a preview of all the applications that have been suspended. Swipe an app's preview from the top of the screen to shut it. You may also set your smartphone up so that some apps can run even when they aren't being utilized.

To do so, go to Settings>Apps> Background App Renew and check the boxes next to the apps you want to refresh in the background. Go to Settings-> General-> Background App Refresh on your iPhone to work on these settings.

A list of programs that are currently authorized to operate even when they are not open can be found in this menu. If you don't believe it's vital for applications to stay open, then don't do it. you can just turn off Background App Refresh instead.