Ring/Silent Switch and Vibrate Modes
A switch on the side of iPhone makes it easy to turn the ringer on or off.Turn the ringer on or off:
Flip the switch on the side of iPhone.
IMPORTANT: Clock alarms still sound even if you set the Ring/Silent switch to silent.
Set iPhone to vibrate:
In Settings, choose Sounds. Separate controls let you set vibrate for both ring mode and silent mode.For more information, see Settings.
Source
