I just logged into the email address of 189, and I don't know how to send short messages.

Mobile phone users can write short messages themselves, or they can call the system's own short message warehouse to send short messages. The short message warehouse supports sending short messages to many friends in the address book. Click "My SMS" in the function menu on the left to open the mailbox and enter the SMS sending page. If you need to use the short message in the short message warehouse, you can click "Short Message Warehouse", select the required short message content, enter the mobile phone number of the recipient, and click "Send".