Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello GrahamTiplady,
Welcome to Microsoft Community.
I am a Microsoft user just like you, I hope you are doing well?
Do you mean you are the owner of an Microsoft 365 Family subscription and you want to see the members of your Family subscription?
If yes, go to https://account.microsoft.com/services and choose Sharing to see all the members of your Microsoft 365 Family subscription.
If you want to see devices you have installed Microsoft 365 from your account:
Go to your Microsoft account, Installs page and sign in using your Microsoft account, if prompted. https://account.microsoft.com/services/office/install and check under Devices.
Please let me know if you need more assistance.
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Warm Regards