If you are using an Exchange account, you can auto reply a specified message for the received emails with setting the Out of Office Assistant while you are away. Please do as follows:

1. In the Mail view, select the exchange account on the Navigation Pane, and click File > Info > Automatic Replies.
Note: If your outlook have not connected to an Exchange Server, you can't find the Automatic Replies option.

2. In the Automatic Replies dialog box, (1) select the Send automatic replies option; (2) check the Only send during this time range option and specify the Start time and End time as you need; (3) type the replying message in the below box. See screenshot:

3. If you need to enable auto-reply for external senders too, please (1) click the Outside My Organization (On) tab; (2) check the Auto-reply to people outside my organization option; (3) type the auto replying message in the below box. See screenshot:

4. Click OK to activate the out of office message.

If your outlook haven’t connected to an Exchange Server, the above method will not work. In this situation, the Manage Rules & Alerts function of Outlook can help you to set out of office auto reply as following steps:

1. Click Home > New E-mail to create a new message, type the subject and message as you need. See screenshot:

2. The click File > Save As in the new message window.

3. Now in the Save As dialog box, please select Outlook Template (*.oft) from the Save as type drop down list, and click the Save button. See screenshot:

Note: After specifying the Save as type as Outlook Template (*.oft), the email will be saved to the default template folder automatically. And it's not necessary to choose saving folder any more.

4. Go ahead to click Home > Rules > Manage Rules & Alerts, see screenshot:

5. In the Rules and Alerts dialog box, (1) click E-mail Rules tab; (2) select the email account that you want to apply the out of office setting from Apply changes to this folder drop down list; (3) and then click New Rule. See screenshot:

6. In the Rules Wizard , click Apply rule on message I receive from the Start from a blank rule section, and click the Next button.

7. In the Rules Wizard (which condition(s) do you want to check), check the sent only to me option, and click the Next button. See screenshot:

8. Now in the Rules Wizard (what do you want to do with the message?), please do as following screenshot shown: (1) Check the reply using a specific template option; (2) Click the linked text of a specific template; (3) Now in the popping out Select a Reply Template dialog box, select the User Templates in File System from Look in drop down list, click to select the message template you created just now, and click the Open button; (4) Now you return to the Rules Wizard, please click the Next button.

9. Click the Next button twice to get into the Rules Wizard (Finish rule setup), please (1) type a name for the new rule in the Step 1 box; (2) check options as you need in the Step 2 section; (3) and click the Finish button.

10. Close the Rules and Alert dialog box.

Going forward, when new emails are coming in your Outlook, they will be automatically replied with the specified message template at once.

The above method is somewhat troublesome and tedious for you to set them step by step. But here I will introduce you an easy and handy way to set out of office quickly and conveniently in Outlook.

1. Click Kutools > Reply > Enable Auto Reply to activate this utility.

2. Get into the Auto Reply Manager by clicking Kutools > Reply > Auto Reply Manager. Check the Account Name that you want to apply this function, and click the OK button. You can also edit the subject and auto reply text as your need. See screenshots:

And now the auto reply setting has been successfully set up.

Tip: Once closing the Outlook application the Auto Reply feature will stop working.