ITIL (Information Technology Infrastructure Library) is not user-defined; rather, it is a set of best practices and guidelines for IT service management (ITSM). It provides a framework to manage IT services efficiently and effectively, aligning them with the needs of the business and ensuring that IT supports business objectives.
Over time, it has evolved and gained widespread adoption globally as a standard for IT service management.
The ITIL framework consists of a series of books that cover various aspects of IT service management, including service strategy, service design, service transition, service operation, and continual service improvement. It also defines processes, roles, and responsibilities within IT service management to ensure a consistent and structured approach to managing IT services.
Since ITIL is a set of best practices and guidelines, it is not meant to be user-defined. However, organizations can adapt and tailor the ITIL practices to suit their specific needs and circumstances while adhering to the fundamental principles of the framework. This adaptability allows organizations to implement ITIL in a way that aligns with their unique business requirements and IT environment.