The document discusses the Software Development Life Cycle (SDLC), which defines the stages involved in developing software. It describes the typical phases as requirement gathering, design, implementation/coding, testing, deployment, and maintenance. The SDLC helps make the development process more systematic and efficient by defining these stages and guiding the software from requirements to maintenance. It also improves estimates of budgets, resources, and time required. Common SDLC models mentioned are waterfall, iterative, spiral, V-model, and agile.