Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
If the product key has already been redeemed, you don't need the key again. It is associated with the Microsoft account used when it was redeemed.
If you purchased it through the Mac App Store: open the App Store on your Mac, sign in with the Apple Account used for the purchase, and download the Microsoft 365 apps again. Then sign in with the Microsoft account associated with your subscription.
If you purchased it directly from Microsoft**:** sign in to the Microsoft account used for the purchase and check your subscription here:
https://account.microsoft.com/services
If Microsoft 365 Personal is listed as an active subscription, select Install to download the apps.