A transaction processing system is a type of information system. Transaction processing system collect, store, modify, and retrieve the transactions of an organization. A transaction is an event that generates or modifies data that is eventually stored in an information system. For considering a transaction processing system, the computer must pass the ACID test. The essence of a transaction program is that it manages data that must be left in a consistent state. E.g., If an electronic payment is made, the amount must be both withdrawn from one account and added to the other; it cannot complete only one of those steps.