How to Change to Vibration on the iPhone

The iPhone comes with various sound customization options when receiving calls, text messages or other notifications, all falling in one of two notification settings: Ring or Silent. For instance, you can enable vibration for Silent or Ring mode, allowing you to get an extra level of notification in case you cannot hear your phone. Enable vibration using the iPhone's built-in sound customization options.

...
Enable vibration on your iPhone.

Step

Choose "Settings" from the iPhone's home screen.

Step

Touch "Sounds."

Step

Slide the "On/Off" switch to "On" next to Vibrate in the Silent section.

Step

Slide the "On/Off" switch to "On" next to Vibrate in the Ring section.