How does Apple send text messages?

There are many social software that can let us communicate with others, but the short message function of mobile phone can't be completely replaced. How does Apple send text messages?

How does Apple send text messages? 1. Open the information APP on the mobile phone desktop.

2. Click the "Write" button in the upper right corner, enter the information and click Send.

Or choose an existing conversation, enter the short message content and send it.

This paper takes iphone 12 as an example and applies it to iOS 15 system.