The Out-of-Office Assistant is missing
Out-of-office Assistant is for Microsoft Exchange mailboxes only. Look for it on the File menu is Outlook 2010 or on the Tools menu in older versions.
If you don't have an Exchange mailbox, you'll need to replicate it's actions using Rules Wizard, or better yet, use your email server's "vacation reply" feature to send out-of-office replies. When you use Rules Wizard to send Out-of-office replies, Outlook needs to be running and checking mail regularly for the reply to be sent. Using your server's "vacation reply" feature allows the response to be sent when the message arrives, not when Outlook downloads it.
Inbox and Outbox Assistant commands are grayed out
The Inbox Assistant and Outbox Assistant features are for Exchange mailboxes only and therefore, work only if you connect to Microsoft Exchange Server.
If you don't have Exchange Server, you'll need to use the Rules Wizard in Microsoft Outlook or check out the alternatives below.
Email Responder plug-in for Microsoft Outlook is an out-of-office assistant. Auto reply with away message templates; change your status and reply templates remotely. Change or schedule your free-busy status manually (Away, Out of Office, Vacation, Tentative, Custom) or use you Microsoft Outlook Calendar or Skype availability status. Auto response to selected Contacts or Distribution lists only. Enable Microsoft Outlook auto forward. Windows 10 and Outlook 2016 support.
Auto-Mate is an Outlook utility that allows you use define rules to move mail from your Inbox (or other folders) based on several criteria, including the age of the message. While Outlook rules only run as messages are downloaded or when you click Run Rules now, Auto-Mate rules run on a schedule, enabling you to apply rules to messages that have been in your Inbox for a given number of hours, days or weeks. Available in Standard or Pro Version. Outlook O365, Outlook 2019 as well as Outlook 2010, 2013, 2016, 32 and 64 bit editions. Version 12.
AutoReply 365 works with Office 365 and has the following features: The subject line of autoreply message consists of "Autoreply:" prefix and the Subject line of original message. The body of autoreply message includes the original message text. You can set any From: address for autoreplies. You don't need to create a shared mailbox for autoreplies.
AutoReply Flow checks the original message for a Reply-To: address field. If one is found then an auto-reply message will be sent to this address. If an original message has no Reply-To: address field then an auto-reply message will be sent to the From: address of the original message. The subject line of the auto-reply message consists of the prefix ("Confirmation:", "Autoreply:" etc) and the Subject line of original message; the body of auto-reply message will include the original message text.
Exchange/Outlook add-on to create custom replies, forwards, signatures -- inserting any type of boilerplate text into your message. Templates are stored in Outlook or Exchange folders and can contain scripting elements (in VBScript or ET's own script language) to build replies that use information from the incoming message. Various extensions can handle such tasks as mailing list subscriptions. For a rotating quote, download the Rotating Text template. Has some issues with Outlook 2002 -- make sure you get the latest update, disable RTF templates, and don't try to use ET as a custom action in Rules Wizard.
Mail organiser for Outlook to replace the built-in Rules Wizard. Offers unlimited rule capacity (only limited by your computer hardware), quick folder find, attachment renaming, and Bayesian antispam mail filtering.