Normal: this is the default normal mode.
Personal: This suggests that the message is personal. When the recipient opens the message, they will see ‘please treat this as personal’ in the info bar.
Private: This suggests that the message is private. When the recipient opens the message, they will see ‘please treat this as private’ in the info bar.
Confidential: This suggests that the information is confidential. When the recipient opens the message, they will see ‘please treat this as confidential’ in the info bar.