There are different ways record the processing fees in QuickBooks, Mirta.
You can either include it when you deposit the invoice payment, or create an expense transaction that affects the processing fee account.
Here's how you can include the processing fee in the deposit:
You might also want to reach out to your accountant about this. They can provide additional options that suit your company setup. They know what's best for you and your books.
I'd be glad to further help you if you have more concerns.