Why does my mobile phone activate iMessage, but I send messages or text messages to others (the other party is also Apple, and he can receive messages from others)?

First of all, in the setting information, look at the sending and receiving location below, and click in to see the address.

Use the address here when sending a short message to the other party. It is suggested to add the email address to the other party's address book.

In addition, it is suggested to add +86 in front of the other party's mobile phone number in the address book. +86 refers to China, and iMessage is universal, so the number should be complete and easy to identify.

If they are all set in this way, there should be no problem. If you send a text message to your mobile phone number, try using a bound email address.