When your iPhone is in your pocket or bag, a vibration helps to inform you about an incoming call or text if you’re unable to hear the sound of your alert tone. If you’re in a quiet place like a library, it’s even more important to ensure your iPhone vibrates instead of rings so that you don’t disturb others.
To ensure your iPhone can vibrate to notify you at all times, here’s what you can do when you notice your iPhone is not vibrating on Silent or Ring mode.