A mail group address is the collection of email addresses of its group members. When a sender sends an email to this mail group, all group members can receive the email to achieve the effect of sending a mass email. If the members of the mail group want to send or reply to the members of the mail group, all the members of the mail group can receive the mail as long as they type the address of the recipient, which is convenient for the members of the mail group to communicate with each other.