Prepaid travel cards are cards you can use overseas to pay in local currency for all your purchase needs, from hotel bills to corner convenience stores. You buy the currency and place it on the card before you leave Australia. The currency exchange rate is set, so you know how much things will cost overseas with one exchange rate.
In addition with a prepaid travel card you can withdraw local currency from ATM’s marked with a Mastercard or Visa logo. You use your 4 digit pin, similar to Australia, to withdraw money overseas. The cards are like an Eftpos card overseas and if they are with Mastercard or Visa, you can use them almost everywhere.