For Microsoft Office Outlook 365
Step One: Click the File tab, and then click the Info tab in the menu.
Step Two: Click Automatic Replies (Out of Office).
Note If you do not see this option, you are not using an Exchange account. Please go to this section: How to enable Automatic Replies in non-exchange account.
Step Three: In the Automatic Replies dialog box, select the Send Automatic Replies check box.
Step Four: If you want to specify a set time and date range, select the Only send during this time range check box. Then set the Start time, and then set the End time.
Step Five: In the Inside my organization tab, type the message that you want to send within your organization, and in the Outside my organization tab, type the message that you want to send outside your organization.
Click OK.
If you selected the “Only send during this time range” option in step 4, the Automatic Replies (Out of Office) feature will continue to run until the date and time set for the End Time in step 5 is reached.
Otherwise, the Automatic Replies (Out of Office) will continue to run until you repeat step 1 and select the “Do not send automatic replies” option.
If you receive an error trying to set up the Automatic Replies in Outlook 2013, please refer to the "Your Automatic Reply Settings Cannot Be Displayed" article.