SAP is an enterprise resource planning software that manages business processes like finance, supply chain, manufacturing, and more. It uses a 3-tier client-server architecture and ABAP as its proprietary programming language. SAP's modules are organized into functional areas like finance, sales, production, and more. Implementing SAP requires configuration of the software to meet a company's needs through customization, interfaces, and data conversion programs. SAP licenses are based on the number of users and their level of access. The enterprise structure in SAP defines how a company is organized in areas like finance, purchasing, and sales for reporting and transaction purposes.