customer paying their invoices by credit card

You can add a negative line item when making a bank deposit, ametz1201. Let me guide you through the process.

In QuickBooks, add negative amounts for the fee together with your transactions when generating the deposit. Here's how:

1. From the Bank Deposit window, scroll down to the Add funds to this deposit section.
2. Enter the fee as a line item.
3. Choose from whom the fee was received in the Received From section.
4. Select Bank Charges from the Account ▼ dropdown.
5. Enter the amount fee as a negative number. For example, if the fee was US $5, enter –5.
6. Review the deposit total with the bank fee. Once everything's good, click Save and close.

On the other hand,  you can create a service item for the credit card fee and manually add it as a line item on your customer's invoice. Follow the steps below:

1. Go to Sales then choose Products and Services.
2. Click on New then select Service.
3. Enter the name of your service item. 
4. Select the account you'd use to track our processing fees under the Income account drop-down.
5. Once done, click Save and Close.

Add the fee as an additional item on your invoice every time you charge your customers with the credit card. For more details, open this article: Manually add service fees to invoices in QuickBooks Online.

I'm also adding this resource to learn more about recording invoice payments and how to personalize your sales forms:

• Record invoice payments in QuickBooks Online
• Customize sales forms

Let us know if you have any other concerns about adding fees to invoices. I am always available to assist you. Have a wonderful day!

@ametz1201 

If you are B2B, you can use a 3rd party processor to accept payments for free.