Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
First of all, do you know the exact Microsoft 365 product you referenced here?
Microsoft 365 is a very broad term, within it, there's Microsoft 365 basic, personal, family for example on the consumer side, then there's Microsoft 365 business basic, standard, premium for example on the commercial side.
To manage them the instructions are different and the account used to log in is also different, support path is also different..
So it would be very helpful if you know which Microsoft 365 product you have so I can direct you to the right place.