What’s the meaning of Blue and Green colours on my iPhone sent messages?

Have you ever noticed on your iPhone that when you send messages, some are in green and some in blue? Some of you may already know this but for those who are curious, here is why:-

iphone_greenGreen is for SMS (short messaging service) text Message.
This is the ‘traditional’ text message that is automatically used when sending a text to someone without an Apple device, for example if you are sending message to any smartphone other than iPhone (such as Windows, Android, Blackberry). Regular texting rates apply depending on your phone provider’s texting plan.

iphone_blueBlue is for iMessage.
This works only on iDevices. The iMessage is sent over an internet connection. There are no text charges by your phone provider but a small amount of data is used when your iPhone is not connected to a WiFi network.

This is all done automatically if an iMessage is activated in your iPhone as well the recipient’s iPhone (Tap Settings, Messages, then check to see if the feature is switched on.  If it is, you should also activate “Send as SMS”)