Joke Collection Website - Blessing messages - How does Apple switch between blue and green when texting?

How does Apple switch between blue and green when texting?

1. When both parties are Apple phones and the IMESSAGE function is turned on, the bubble will be blue; When the network signal is bad, or the other party is not an Apple user, or the IMESSAGE function is not turned on, the information bubble will be green.

2. Specific steps: When both mobile phones are Apple phones, the messages sent to each other are upgraded to imassage, and the information turns blue.