The drop box is an online form that a student fills out and sends to his or her professor with complete anonymity. No e-mail can be traced back to the student by the professor. Students provide a pseudonym (Ms. J), their class name, time of class, name of their professor, comments about the document they are attaching, their attachments (up to three), an email address if they would like to receive confirmation from the faculty that their faculty member received the attachments.
Keep in mind that professors never see the student email address, so they would never know that Ms. J is actually sally.jones@marquette.edu.