You'll have to visit the Billing & Subscription menu from the Account and Settings page in QuickBooks Online (QBO). This way, you're able to find your Company ID and manage your subscription accordingly. Let me guide you how.
Additionally, here's an article that'll further guide you in managing the growth of your business using QBO: QuickBooks Help Articles. It includes topics about account management, banking, and expenses to name a few. You'll have to click the + More topics button to view more selections.
Let me know if you have other concerns about managing your QBO account or inquiries. I'm just around to help. Take care always.