How to add payment processing fees to invoice if the client chooses to pay with Credit card or ACH?

I'm here to provide information about the adding the fee, KT1616.

While the program doesn't have an automated way to directly charge your customers for the fee, you have the option to manually include it in their invoices and pass that cost on to them.

First, let's create dedicated service item for the fee. This will allow you to include it along with a detailed description on your invoices. Here's how:

1. Go to the Gear icon.
2. Select Products & services.
3. Click New, then choose Service.
4. Enter the name of the fee item.
5. From the Category dropdown, select the category that best describes the fee.
6. Fill out the rest of the fields.
7. Select Save and close.

Once done, refer to the Step 2 section of this article to be guided in including the service fee to your customer invoices: Manually add service fees to invoices in QuickBooks Online.

In addition, feel free to read these articles to learn how to personalize your sales forms and enter customer payments in QuickBooks Online: 
 

• Record invoice payments
• Customize invoices, estimates, and sales receipts

Feel free to comment down below if you have any follow-up questions about QuickBooks Payments. The Community is always here to help. Have a wonderful day.

@KT1616 

QB Payment doesn't offer such feature. If you are B2B, you can use a 3rd party payment processor with the feature.