Information systems project management involves coordinating the activities of a team of experts from various fields to create and improve software products. Planning and executing such projects often encounter challenges such as poor design, lack of organization and ineffective management, further compounded by limited resources and increasing competition. Successfully managing such IT projects crucially depends on understanding the Software Development Life Cycle (SDLC), which describes all development phases including planning, design, development, testing, delivery, and maintenance of the software. Agile development models, such as SCRUM, are becoming increasingly popular as they emphasize collaboration, communication, and incremental changes for faster adaptation and better project management. In addition to development, it is important to manage the maintenance of existing systems to preserve the functionality and stability of software in line with technological advancements and changing user needs, as well as increasing security updates and compliance with sensitive data protection policies which are significant topics in today's international regulations. Software maintenance process also includes ensuring sustainability, involving the development of socially important characteristics of software as a product with extended lifespan and adaptability to changes. By maintaining software alongside adopting sustainable development practices, long-term economic, social and environmental benefits are achieved, both for end-users and society as a whole. Using the case study method, this paper describes true example of the entire development process of an application in detail, outlining the activities of each phase of the development cycle, along with a review of maintenance practices post-delivery, all aimed at maximizing benefits for users.