How does iphone4 turn off SMS and make a prompt sound?

1, enter "Settings" on the desktop;

2. Enter the "notice" at the bottom of the settings;

3. Enter "information" under the notice;

4. Turn off the Permit Notice or select "None" as the following "Notification Sound" and "None" as the vibration.

Method 2:

Just pull down the mute button on the top left of the phone (the one above the volume button) and pull it up again when not in use.