USCIS Guidance on Payment of N-400 Application Fee with a Credit Card
You may pay for your N-400, Application for Naturalization, using a credit card. There is no additional fee to pay with your credit card. The N-400 is the only form that can be paid for by credit card using the G-1450, Authorization for Credit Card Transaction.
Acceptable Credit Cards
You may use Visa, MasterCard, American Express and Discover. You may also use gift cards with Visa, MasterCard, American Express and Discover logos.
I have turned to Rajiv Khanna and his amazing team on a number of occasions. Most recently, to flush out a complicated immigration situation from France. The thing that impresses me most is his humanity, his vast knowledge, professionalism and generosity. Well, those are 4 things, not one. But it is hard to stop when posting a positive comment about Mr. Khanna's office and work. He responds immediately or has a staff member do so, and he will explore every possibility until he finds a solution. In the maze of disappointing immigration attorneys out there, I highly recommend him.