Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Renee,
I assume you are currently on a personal plan?
Microsoft's personal/consumer products and business products are two separate ecosystems - meaning, different username system, different support, different billing, etc. So there's no simple way to switch over/upgrade.
Do you already know which business plan you want? You would need to sign up for it. If you do sign up for the business plan, it will have you create a new username that ends with onmicrosoft.com. Make sure you write that down because that's your user credential to log into the apps after that. And the subscription will be managed via this link https://admin.microsoft.com, with this same username / credential. Your personal account username will NOT work here.
Signing up for the business plan doesn't automatically cancel your personal plan. You still have to cancel it yourself. Please go to https://account.live.com
Sign in to your Microsoft account. Then go to Services. Click on Manage for the subscription plan you want to cancel.