Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Dear Liz,
Thank you for reaching out to the Microsoft Community.
Base on your description, that you have a lot of accounts, but you don’t know which or linked to the Onmicrosoft account. I will listed out the account you have said is 2 personal account and one that you use to set up for the kid Xbox.
First, I want to confirm with you that personal account and business account are separated, they are not related to each other. The personal account could also use the O365 feature, and they also can have subscription.
For more information, could you please follow some step that I suggest below:
Microsoft Admin Center
Since you have an onmicrosoft.com business account, you should have access to the Microsoft Admin Center (admin.microsoft.com). Log in and check which user accounts are associated with your business domain. This should clarify whether your .com and .co.uk accounts are officially part of the organization.
If your personal accounts have IMAP emails assigned, check how emails are being delivered. Are they forwarded or synced to your business account? You might also check Outlook settings at outlook.com to see if your business and personal emails are linked in any way.
Check for subscriptions & Services
Sign in at account.microsoft.com using each account. Navigate to Subscriptions & Services to check if multiple accounts are using the same Office 365 subscription.
If you have any other questions or need further assistance, please feel free to let me know.
Thank you for your precious time. Have a nice day.
Best regards,
Julie-Hu - MSFT | Microsoft Community Support Specialist