Hi @kjh
Welcome to our forum!
As i know: The "More Apps" group is designed to keep the sidebar organized and consistent across different Microsoft applications. This helps users quickly find and access the apps they need without cluttering the main sidebar.
It provides solutions to help you better interact with Outlook and complete tasks on your messages and appointments without leaving Outlook. Some Apps are installed by your email administrator, but you can install other ones from the Office Store. Please refer to the article and try to install an App from the Office Store.In addition, you can customize the sidebar according to your needs by right-clicking icons > pinning frequently used apps.
Hope it helps!
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