This document discusses documentation techniques used in accounting systems. It begins by outlining the purpose of documentation and why accountants need to understand documentation. The two most common documentation tools - data flow diagrams and flowcharts - are then explained in detail. Data flow diagrams graphically show the flow of data through a system using four basic elements: data sources and destinations, data flows, transformation processes, and data stores. Flowcharts depict the flow of data, documents, or information through a system using standard symbols. The differences between data flow diagrams and flowcharts are explored through an example.