You most likely have faced the situation when your opened app is frozen, it can not be closed and you are stuck. To deal with the situation you can force the app to close. And today, I will share the tips to do so for you.
1. Press and hold down the sleep button of your iPhone until Slide to Power Off menu shows up:
2. Now keep pressing and holding the home button to make the app finally quit.
3. When the app is quit, you'll be directed to the home screen.