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 just got my GC approved through the Offices of Rajiv S. Khanna. Over the last four years I had a very good experience with all the professionals who handled my case at your offices. After so many years waiting at the labor certification stage (PBEC story), they helped me to put together the I-140/485 application, with timely and to-the-point responses to my questions along the way, is a short time. As a result, my application got approved within a couple of months way before my expected timeline. Many thanks to Richa, Amrita (LC stage) and Mathew, Rita (I-140/485) for a job well done. Keep up the good work.