When making a payment, it is not possible to choose a different currency. The payment must be made in the currency of your country of residence. If your country is not listed, then the payment is to be made in US dollars.
If a friend in another country is paying for you, the payment must still be made in the currency of your country of residence (or in USD if your country is not listed). In other words, your friend cannot pay in the currency of their country of residence.