How to use iMessage between mac and iphone?

The operation that iMessage uses between mac and iphone is:

Step 1: Click the "Settings" icon on the desktop.

Step 2: Open "imessage":

Step 3: Enter an Apple account and click the "Login" option.

Step 4: After the system is verified, it shows that iMessage is activated and turned on:

Step 5: Click the "imessage" icon on the desktop.

Step 6: Click the blue plus icon in the upper right corner, open the address book on the iPhone, and select the contact who wants to send the mac:

Step 7: Enter the information content and click Send.