I'd love to help you get past the credit card issue that you've encountered, @CrystalK.

If you're referring to charging the credit card of your customers, the solutions shared by my peers above will do the trick. However, if you've received any errors while doing the process, I'd appreciate it if you can share some more details.

On the other hand, if you mean to change your billing details, so your credit card will be charged for the subscription, I can guide you on how to do that.

Here's how:

1. Sign in as the Primary or Company Admin.
2. Go to Gear icon⚙.
3. Select Account and Settings. 
4. From the left menu, select Billing Subscription.
5. Select Edit ✎ beside your payment method. 
6. Update your credit card info.
7. Make sure the address in QuickBooks is the same as the one on your credit card statement.
8. Once everything’s good, select Confirm card or Save. 

For more details about this process, please see this link: Learn how to change your billing info, payment method and plan subscription level.

I'm always up to help if you need anything else, @CrystalK. Just let me know by leaving a reply below. Have a good one!