The currency on the island of Curaçao is the Antillean guilder or ANG. It´s also called NAF (Netherlands Antilles Florin).
In most shops and restaurants you can use your credit or debit card.
Also, there are many ATMs where you can withdraw money. Even if you are just at the airport. In the building itself, but also beyond.
Withdraw using an ATM cost money, regardless of the amount that you are recording. Therefore do not withdraw small amounts, but eg. the maximum per day and store that in the safe. Take only cash in your wallet that you expect to need for that day.