The Software Development Lifecycle (SDLC) is a structured process that guides the creation of software from initial planning through design, development, testing, deployment, and ongoing maintenance. SDLC helps organizations build high-quality software efficiently by breaking down the work into clearly defined phases, each with specific goals and deliverables. This approach reduces risks, improves project management, and ensures that the final product meets user requirements and security standards. Common SDLC models include Waterfall, Agile, and DevOps, each offering different methods for organizing and managing software projects.