Hi @Alan Barton
Thank you for posting question to Microsoft Q&A.
Microsoft 365 is the name of the subscription service, not a single application. When you have a Microsoft 365 subscription, it gives you the license to use a collection of individual apps like Word, Excel, PowerPoint. So, the Word application you are already using on your MacBook Air is your Microsoft 365 Word. You will not find a separate app named "Microsoft 365" in your Applications folder; you will only find the individual programs.
Could you please check in the Word app by going to the Word menu > About Microsoft Word and provide me with a screenshot?
Alternatively, you can verify it online. Open a web browser, go to https://account.microsoft.com/services, and sign in with your account. You should see your active Microsoft 365 subscription listed clearly on that page.
If you are still unable to install Outlook through the App Store or your Microsoft Account page, you can download the installer directly. The correct and safe alternative is to use the official installer repository provided by Microsoft.
Please go to the official Update history for Office for Mac page > Update history for Office for Mac
This page contains download links for the standalone installer packages (.pkg files) for various recent versions of Outlook. Find the version you want and click the download link for the Outlook package. Once installed, open Outlook and sign in with your Microsoft Account to activate it.
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