Office 365 (Outlook on the Web) - Turn Off Conversation View
If you do not want to see all emails grouped together, follow these instructions to turn off conversation view. This will show all emails separately in your Outlook mailboxes.
How to turn conversation view on and off in your Office 365 inbox.
1.Log in to the Outlook Web Application
2. Select Outlook.
3. Click the gear icon (Settings menu), located on the upper right-hand side of the screen. Then select off in the conversation view section