The currrency in Morocco is called dirham and is usually written as MAD or Dh.
The currency is non-convertible, which means that you cannot take the currency out of the country (only a small amount) and it is not possible to to exchange dirhams in other countries than Morocco.
Payments in Morocco is usually done with cash. ATM’s are easy to find in the cities.
More and more places accept visa and credit cards, such as riads and hotels and some shops and restaurants, but it is advisable to check this upfront.
It is a good idea to bring a small amount of Euro or Dollar as reserve, say if you for example don’t find an ATM immediately and you need to pay the taxi from the airport.