"[MARKETING]" inserted at the beginning of the subject line of a Marketing Cloud email
|Knowledge Article Number||000213213|
You may see "[MARKETING]" inserted at the beginning of an email subject line because some company mail servers add it or a similar word for emails from commercial mailings. For example, the email subject line should be "Your Monthly Newsletter," but when the email is received it shows as "[MARKETING] Your Monthly Newsletter."
Marketing Cloud does not insert this word into the subject line. You can verify whether the word or phrase is added due to your internal mail server's policy by sending the email to an external email address (such as Gmail, Yahoo, or Hotmail) that you can access.