There’s great wealth found all over the world, and banks are somehow associated with almost all of it. There are local and International banks. International banks offer financial services, such as lending opportunities, and payment to people in foreign countries. This payments can be to individuals or companies.
Every international bank has its own policies outlining with whom they do business. Companies do business with international banks to help facilitate international business, the complexities of which can be quite costly. Individuals work with international banks for a number of reasons, including tax avoidance. You've probably heard of offshore bank accounts and Swiss bank accounts.