Apple sends messages. What is the difference between blue and green?

The blue and green of this message represent different ways of sending.

1, blue message: refers to the message sent through Apple's iMessage service. IMessage is a free instant messaging service provided by Apple for its device users (iPhone, iPad, Mac, etc.). ). As long as both the sender and the receiver use Apple devices that support iMessage, and both devices are enabled with iMessage function and have network connection (WiFi or cellular data), the sent message will be displayed with a blue background.

2. Green information: refers to the information sent through the traditional short message service SMS or multimedia message service. This kind of information is not limited to Apple devices, and any mobile phone that supports SMS can send and receive it.