I would like to accept American Express card payments on my invoices but it is not showing as an option.

Hello there, sarah.

You can easily add the ability to accept American Express cards from the merchant service center. Let me guide you on how to do it:

1. Sign in to the merchant service center.
2. Select Account, then select Account Profile.
3. From Payment Methods, select Add American Express.
4. Select Submit.

After that, you can follow these steps to activate invoice payments.

1. Go to Settings , then select Account and settings.
2. Choose the Sales tab.
3. Under Invoice payments, select Edit, then select the payment options you want.
4. Click Save.
5. Hit Done.

You can read this article for more details: Take and process payments in QuickBooks Online with QuickBooks Payments

In addition, you can consider checking this article to personalize and add specific info to your sales forms: Customize invoices, estimates, and sales receipts in QuickBooks Online

If you have further concerns about payments in QuickBooks Online, feel free to come back here in the Community. We're here to assist you 24/7.