iPhone 8 Plus
Ending running applications
Some applications aren't ended completely when you return to the home screen. If you don't end them from the list of running applications, they keep running in the background which may slow down your phone.
Step 1 of 3
Press the Home key twice in quick succession until the list of running applications is displayed.
Step 2 of 3
Slide upwards on the required application to end it.
Step 3 of 3
Press the Home key to return to the home screen.