Hi there, allamericanmechanical.

I'm here to share some details on how you can include the credit card fee in your invoices without changing it every time your customer pays. Let's modify your invoice by changing the payment method option.

Here's how: 

1. Open the invoice that you want to change.
2. Select the online payments that you want to use.
3. Click Save and send once done.

Once you resend the invoice, your payment options will be revised. 

See the screenshot below for your reference.

Feel free to read this article for more details: Add service fees manually to invoices. 

Also, I've got an article about customizing sales forms. It guides you on how to personalize the invoice, estimates, and sales receipts.

Let me know if you have other questions. Take care always and stay safe.