Credit and debit cards can be used everywhere in the USA, but you better also take some cash with you when you travel to America.
A credit card is the most used payment method in the USA, but you always should have some cash at hand. This way you can easily buy a snack from a snackcart at the airport of tip the bellboy when he handled you luggage at the hotel.
Before you leave for America, you can get dollars at you local bank or in an online exchange like GWKTravelex.nl. You can also exchange money at the airport, but this will be more expensive as their exchanger rates are less favorable.