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).