I have a customer that used a second credit card. The system will not let me change it through Sales Receipt. How can I record the new card Number?

It's nice seeing you here in the Community space, @radiantlifesuffo.

I've got some steps on how you can record a new credit card number in your QuickBooks Online (QBO) account.

Firstly, you can view your customer profile and add their credit  card information from there. Keep in mind that you have to connect your payment account first to your QBO account. This way, your customer's info will be saved. 

Here's how:

1. On the upper right corner, look for the Gear icon.
2. Select Account and Settings.
3. Choose the Payments tab.
4. You may now start your setup. Choose either QuickBooks Payments or an Existing account. In the Existing account section, choose Connect account. In the QuickBooks Payments section, choose Set up payments.
5. Review the account info and make sure it's accurate. If everything looks good, select Connect.
6. Once the connection is finished, sign out and sign back into QuickBooks Online for the changes to take effect.

If everything's good, you can now add your customer's credit card information to their profile and I'd be glad to show you how:

1. On the left navigational panel, look for the Sales menu.
2. Select the Customers tab.
3. Locate and select your customer and click Edit.
4. Choose the Payments and billing tab.
5. From the Preferred payment method dropdown menu, select Credit Card.
6. Enter the needed information. Once done, hit Save.

Furthermore, I'm adding these resources for you to be able to learn more about how to process credit cards from your customers:

• Void or refund customer payments in QuickBooks Online.
• Take and process payments in QuickBooks Online with QuickBooks Payments.

Please know that I'll keep an eye out for your response, should you still need further queries. You can drop some comments below. Stay safe and have a good one.