Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
1
Log into your Microsoft account on this link, there, you should find any existing subscription linked to your account:
https://account.microsoft.com/services/
If that indicates a Microsoft 365 subscription, if that is the Personal or Family version, that subscription allows you to install the Office apps on your PC's and you also get 1TB of OneDrive storage, if that is the Microsoft 365 Basic version, that only entitles you to 100GB of OneDrive storage and access to the free Office apps in a web browser.
2
If you are unable to find the subscription on your account, using any Microsoft account you may have, try using the steps they provide on this link to find out what the payment was for.