Users can freely swap back to Classic Outlook by installing it and disabling the modern layout. If you can't find the toggle to switch back, open the "Help" tab and select "Go to Classic Outlook ...

Customize Outlook layout The layout settings allow you to customize various features in the Outlook app, such as "Focused ...

You can use the Outlook Ribbon in a Classic or Simplified layout. Read next: How to add Back and Forward buttons to Outlook Ribbon.