Using New Outlook on Windows for personal email, calendar, and contact management
Hello Chege033,
Greetings!
Thank you for posting on Microsoft Community!
Unfortunately, the Outlook appointment will not show any additional body text including description details unless opening it. It is a by-design behavior.
I will also share feedback portal URL so that you can submit your feedback directly to our product developer team via using this Microsoft Feedback portal.
As a workaround, when you want to see all the notes of an appointment without needing to open the item in its own window via a double click, you can enable the Reading Pane in the Calendar via: View-> Reading Pane
If the above mentioned workaround could not address your concern, feel free to reply and provide more information to us. We will continue to support you.
Thank you for your time and cooperation. Wish you have a nice day