When downloaded from the Mac App Store, Word, Excel, and PowerPoint require an Office 365 subscription to create and edit documents. To send and receive email, Outlook requires an Office 365 subscription. You can activate an existing Office 365 subscription, or use the in-app purchase option to start a new subscription.
One-time Office licenses (also known as perpetual), such as Office 2019 Home & Business, Office 2019 Home & Student, and Volume License are not compatible with Office apps downloaded from the Mac App Store. These licenses can only be used with Office apps downloaded directly from Microsoft.
If a one-time Office license is used with an app from the Mac App Store, you will see a yellow message bar stating No subscription found and the app will be in reduced functionality mode.
If you have a perpetual (one-time) license, but have inadvertently downloaded Office apps from the Mac App Store, you can follow these steps to install the right apps.
Remove and reinstall Office apps
Close Word, Excel, PowerPoint and Outlook apps.
Open Finder, and go to the Applications folder.
Locate Word, Excel, PowerPoint, and Outlook apps, then control-click, and choose to Move to Trash.
Open a web browser, such as Safari, and use these links to download Office apps directly from Microsoft:
Alternatively, you can download all Office apps in a single package.
Once downloaded, open the package to start the installation process. When installation is complete, your Office apps can be activated and used with your perpetual (one-time) license.