currency conversion or foreign exchange

TRANSACTIONS MADE IN FOREIGN CURRENCIES

“Transactions, returns and credits made in a currency other than U.S. dollars will be converted into U.S. dollars. We do not add any foreign exchange rate fee to these Transactions. The conversion will be performed by Mastercard International, the payment network associated with your Account (the "Network"). The Network follows its own methods for conversions that are subject to change. The conversion will occur on the day the Transaction, return or credit is processed by the Network, which may be different than the date of the Transaction return or credit. As a result, the conversion rate may differ from the rate as of a Transaction date or the date a Transaction is posted on your Account.”

https://www.goldmansachs.com/terms-and-conditions/Apple-Card-Customer-Agreement.pdf

You may need to contact MasterCard International or Goldman Sachs.

https://www.mastercard.us/en-us/personal/get-support/convert-currency.html

CONTACTING — Goldman Sachs Bank 

• Using Messages; chat with an Apple Card specialist

• Call toll-free at 877-255-5923; or

• Write to: Goldman Sachs Bank, Lockbox 6112, P.O. Box 7247, Philadelphia, PA 19170-6112.

Whatever rate MasterCard International uses. It’s totally at their discretion. I’ve never seen it disclosed. I can say it averages about 3%. I generally ask the merchant to do the conversion to USD.