In Outlook 365 the Focused inbox separates your inbox into two tabs - Focused and Other. Your most important emails messages are grouped in the Focused tab while others remain in the Other tab. This feature is "aware" by analyzing incoming messages and placing the most important emails in the Focused tab.
To turn off this feature and have all emails in one main Inbox please follow these steps:
- In Outlook select the View tab from the ribbon selection
- Select "Show Focused Inbox" to toggle from the current view