Message settings
To set the advanced message options, open a new e-mail and on the Message tab, in the Tracking group, click the dialog box launcher:

In the Properties dialog box:

- In the Settings area, set any of the following options for your message:
- Click the Importance drop-down arrow and choose the Low, Normal, or
High priority level from the list:
Low priority is displayed as a down-pointing arrow, whereas a High has a red exclamation point. When importance is not specified, the message is given Normal importance.
Note: A standard recommendation is to send:
- The follow-up messages with High Importance,
- Messages with a lot of participants or/and with heavy attachments with Low Importance.
- Click the Sensitivity drop-down arrow and choose one of the following options:
- Normal - Use this option to indicate that the message contents are standard or customary.
- Personal - Use this option to suggest that the message contains personal and, thus, sensitive information. A banner is placed at the top of the message that reads, "Please treat this as Personal".
- Private - Use this option to prevent the message from being edited (text changes, copy, paste, and so on) after you send it. A banner is placed at the top of the message that reads, "Please treat this as Private".
- Confidential - Use this option to indicate that the message contents are restricted or private. The recipient can edit confidential messages. Marking the message Confidential is only to suggest how the recipient should handle the contents of the message. A banner is placed at the top of the message that reads, "Please treat this as Confidential".
- Click the Importance drop-down arrow and choose the Low, Normal, or
High priority level from the list:
- In the Security area, click the Security Settings... button to open the Security
Properties dialog box:
The options convert the message from readable plain text to encrypted text. Only the recipient who has the private key that matches the public key used to encrypt the message can see a readable text. However, any recipient without a private key sees illegible text.
- In the Voting and Tracking options area:
- The Use voting buttons drop-down list allows adding custom voting buttons (see How to add and use voting button in Outlook for more details).
- Use the Request a delivery receipt for this message and Request a read receipt for this message options, if you want to be sure that someone has received your message and read it (see How to request a Receipt for more details).
- In the Delivery options area:
- Use the Have replies sent to option if you want replies to this message to be sent to a different address than the one from which this message is sent.
- Using the option Do not deliver before option, you can schedule the date and time when this message should be sent (see Send an E-mail later for more details).
- The option Expires after is used for time-sensitive messages. After the deadline has passed, recipients will not waste time responding.
See also this tip in French: Paramètres de message.