This is a common roadside mailbox, most platforms show blue or gray mailbox, the red flag is raised and the mailbox is closed, it can indicate the meaning of e-mail, postal delivery. It generally indicates that the mail has been received, and may also indicate that there is a letter to be received. It is recommended to use it with the text. 😊
Note the difference between it and 📭
(open mailbox with lowered flag), 📪
(closed mailbox with lowered flag), 📬
(open mailbox with raised flag).