Focused Inbox for Outlook
Focused Inbox separates your inbox into two tabs, Focused and Other. Your most important email messages are on the Focused tab while the rest remain easily accessible, but out of the way, on the Other tab.
For additional information, and how to turn Focused Inbox on or off, please visit: Focused Inbox for Outlook
If you don't see Focused and Other in your mailbox, you might have a Clutter folder instead. For more information, see Use Clutter to sort low-priority messages in Outlook.