Why can't the analog SMS in Apple's mobile phone be sent out?

The other party needs to open iMessage, and your iMessage is also open normally. Solution:

1. Locate the settings and click Open.

2. Slide to find the information, and then click.

3. Turn off the switch on the right side of "iMessage".

4. Slide down the phone interface and find "Send by SMS".

5. Turn on the switch to the right of "Send by SMS".

My SMS is a kind of MMS, provided that you send it to users who have not opened iMessage or Android, which is the format of MMS.

IMessage is just like WeChat built into the Messages application. If you send a message to another iOS user with iMessage enabled, the send button should be blue and only consume traffic. SMS is green.