How to Use an iPhone on Mute

Speaker

1). Turn the iPhone so it's left-hand side is pointing upwards.
2). Locate the small chrome-colored switch just above the volume controls. This is the mute switch.
3). Flip the switch toward the back of the iPhone. A small red dot will be visible on the iPhone's casing, denoting the iPhone is muted. The external speaker will not make any sounds until the mute switch is returned to its previous position.

1). Bring the iPhone away from your ear while in a call. The screen will illuminate and display the in-call controls.
2). Tap the "mute" button in the upper left corner of the on-screen controls to cut the microphone off. The recipient of the call will no longer be able to hear you.
3). Tap the "mute" button again to switch the microphone back on and allow the recipient to hear you.