The main purpose of cash, non-cash and settlement payment transactions in the financial system is to ensure the regular settlement of obligations between all payment transaction participants. As part of the operations of key institutions, the development of payment transactions is continuously improved. In order to speed up the functioning of payment traffic, the obligatory is regulating an operation of pay systems within all payment service providers. Among the most important providers of payment services in Republic of Croatia, are banks. A goal of the thesis is presenting the payment transaction in detail using the example of Hrvatska poštanska banka, where all users are provided with the most advanced use of a wide range of payment services. Before signing a contract for the use of payment services, it is obligatory that users have to receive all informations on basis of which it will be easier to make a decision to enter into a contract. Over time, payment traffic is digitized, so cashless payment is gaining more and more importance. By joining Croatia into a single euro payment area and the digitization of payment transactions, the development of payment transactions abroad has accelerated.