Buy $1000 Customized Mastercard Mastercard is an international corporation which operates a global financial network. Through this network, it facilitates electronic funds transfers (EFTs) using branded debit, credit and prepaid cards. As an intermediary between financial institutions and businesses, Mastercard supports payment processing by authorizing, clearing and settling transactions.Mastercard holds a substantial global footprint, facilitating transactions in over 210 countries and territories. The network’s reach also spans a variety of financial environments, including retail, e-commerce, governmental organizations and financial institutions.