Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
1
Open Word on your Mac.
On the top menu, click Worde - About Word.
On the resulting dialog box, in the Belongs To section, you should see the Email address of the Microsoft account currently used for the Microsoft 365 subscription.
2
Log into any Microsoft account you may have on this link, are you able to find two separate subscriptions to Microsoft 365 listed?