Autoreplies are a way to send email replies to people automatically. These are used typically when one is away from their office or email and is not responding or checking their email account regularly.
Autoreplies can be set with varying degrees of specificity, including the time span for which it will send replies, to differing messages based on recipients either internal or external to your organization.
The following tutorial demonstrates how to turn on and customize autoreplies from within one's outlook webmail account.