PayPal is the fast, secure way to send and receive money without showing your financial information.
For businesses: It is a system you can use to get paid electronically, in a number of different currencies, without waiting for cheques to arrive and clear. You don't even need a merchant facility to start accepting credit card payments online!
For your customers: It's also a more convenient way to pay online because they don't have to re-enter financial information each time they buy.
They pay from their PayPal account which PayPal then 'refills' by drawing on their credit card, debit card or bank account. In this way the customer can pay quickly and easily without disclosing financial information and feel that your business has their security interests at heart.