Apple can't send messages if it changes its id. What happened?

It doesn't matter if Apple sends information after modifying the id.

However, the iMessage of Apple's mobile phone is related to the Apple ID. If this Apple ID doesn't activate iMessage, you just can't send free iMessage information, which has nothing to do with ordinary SMS.

IMessage is an instant messaging software launched by Apple, which can send short messages, videos and so on. It has high security. IMessage is different from SMS/MMS service of operators. Users only need the data support of WiFi or 3G network to complete communication. IMessage uses the new message reminder system of iOS and Mac os, which can directly push information to the other party's screen, regardless of whether the other party is in the game or locking the screen. If both parties are using iMessage, you can see the state of each other's speech.