You'll want to make sure your credit card on file is up-to-date to prevent account suspension. QuickBooks will automatically charge your account on the next billing cycle.
If you need to update your billing information, here are the steps.
Sign in to QuickBooks Online as a primary admin.
Go to Settings ⚙, then Account and settings.
Select Billing & Subscription.
Next to your payment method, select Edit ✎.
After saving your change, the payment method will be displayed on the Billing & Subscription page.
Check out these articles to help manage your subscription to QuickBooks Online.