Apple 13 has no chat box for texting.

Open a new chat window, and then click the small triangle to the right of "Send". At this time, you will find a "message mode" in the drop-down box that appears, and there must be a tick in front of it. If you click "Message Mode", the previous check will disappear and you can chat with your friends again. After sending a message, the chat window will not close automatically.