Flags and reminders can help you and others remember to do things. To add a flag or a reminder (or both) when you're creating a message, start by clicking Follow Up in the Options group of a new e-mail message.
Follow up for yourself
Suppose you send a message to a colleague that says "I'll follow up with you tomorrow." To be sure that you remember to do that, flag the message for yourself by clicking Follow Up and then clicking Tomorrow. The message (which is moved to the Sent Items folder once you send it) is flagged and added to your To-Do List in Tasks list. It also shows up as an item on your own To-Do Bar.
Follow up for the recipient
You can also attach a follow-up flag for your recipients by using the Flag for Recipients command. We've highlighted the command to do this in the picture. Before you send the message, you specify when you want the recipient to be reminded to follow up with you.
As you can see in the picture, the received message will include a flag and the bell icon (indicating that the message includes a reminder). As long as the recipient keeps the message in his or her Outlook mailbox, a reminder will be displayed at the time you specify. (Note that the item will NOT be added to the recipients To-Do Bar — creating a to-do list is a matter of personal choice.)