Office 365 (Outlook 2016 for Mac) - Modify Message Settings
This document describes how to access additional settings for email messages in Outlook 2016 for Mac.
In Outlook, go to the Outlook | Preferences... menu and select the appropriate category from the row labeled "Email"
Select Reading to configure when mail is marked as read, how conversations are expanded, how IMAP messages are handled, and what is and is not automatically downloaded for security.
Select Composing from within 'E-mail' section. This opens up the window where you can configure your replies and forwards, which attributes are retained from the original message in the reply, and how the reply is formatted.
Select Signatures to configure your signatures and to control when and how they are used.
Select Rules to control how mail is automatically routed between default folders or folders that you have custom created.
Select Junk to configure and examine what is classified and routed as junk mail.
Make your desired changes in the appropriate window, then close the window to save changes.