How to turn on iMessage function on my iPhone? I want to save money on text service charge when I am at home with Wi-Fi.

When your iPhone is connected to the Internet with your home Wi-Fi, you should turn on iMessage function to send and receive messages. This will avoid test service and celluar data charges from your wireless carrier.

1. Go to "Settings > Messages". You see a list of settings for the Messages app.

2. Turn on the "iMessage" switch. The "Messages" app will behave as below:

• Use the iMessage technology over Wi-Fi Internet connection, if available.
• Use the iMessage technology over cellular Internet connection, if Wi-Fi is not available.
• Use the MMS technology, if Internet connection is not available and the message is large.
• Use the SMS technology, if Internet connection is not available and the message is small.

You can turn off the "iMessage" switch, if you only want to use MMS and SMS technologies.

The picture below shows you how to turn on iMessage function on your iPhone:

⇒ Requirements on Using iMessage

⇐ What Is iMessage

⇑ Using Messages App on iPhone

⇑⇑ Apple iPhone - Frequently Asked Questions