Includes the acquisition of goods and services from other entities, and the settlement of amounts owing on these. Includes costs incurred in adding value to resources. The commercially available packages combine these different application systems as modules of the complete package. We can further break down each application system into inputs, processing, storage and outputs. The purpose of the input system is to capture transaction data.
Source documents provide the physical evidence of inputs into the transaction processing system.
Paper Based Input Systems. In paper based input systems source documents, such as purchase orders, receiving reports and sales invoices are filled in manually. Normally pro forma source documents are prepared which contain boxes for each required input field. These forms should be pre-numbered to facilitate good internal control. When transferring a batch of source documents to data processing a batch control form should be prepared and attached to the batch.