This method will filter your results for the session; as soon as you log out and re-open the app, you’ll lose the filter and will need to follow these steps again.
If you’re using the Outlook website, you’ll see Filter on the right side of the page, above your inbox. [2] X Research source
You can create a folder that will only display unread messages when you access it. You’ll be able to see that folder every time you use Outlook.