Visa and Mastercards

What is the primary role of Visa and MasterCard? How is it different to banks offering the cards?

Would like to understand what exactly does a visa or a mastercard offer and why does all credit/debit card offered by banks have to be one of these.

Public Comments

1. Visa and MasterCard are associations that operate the networks that allow the merchants to send transactions to the banks. The Banks issue the cards. All credit cards do not have to be one of these, but if a bank issued an independant card, it would be difficult for merchants to collect money from the bank.