You can use the Messages app on your iPhone, iPad or iPod touch to send messages. Those messages will be sent as iMessage or SMS/MMS. Find out more about the difference between the message types.
iMessages are texts, photos or videos that you can send to another iPhone, iPad, iPod touch or Mac over Wi-Fi or cellular data networks. These messages will always be encrypted and appear in blue text bubbles. To turn iMessage on or off, go to Settings > Messages.
If you're not using iMessage, you can use SMS/MMS. These messages are texts and photos that you can send to other mobile phones or another iPhone, iPad or iPod touch. SMS/MMS messages won't be encrypted and will appear in green text bubbles on your device.
To use SMS/MMS on iPhone, you'll need a text messaging plan. Contact your wireless carrier for more information. You can also set up your other Apple devices to send and receive messages from any Apple device.
If Wi-Fi is unavailable, iMessages will be sent over cellular data. Cellular data rates may apply.