E-mail, not E-mail, means that e-mail is a general term for all e-mails, and QQ e-mail is a kind of e-mail and belongs to e-mail. Matters needing attention in the use of e-mail, confirm the relationship between the recipient and the cc, specify the contents of the e-mail body simply and clearly, prepare multiple e-mail signatures, and add the function of sending and receiving mobile e-mail in the attachment.