Project goals can be reached in different ways, and only a concrete process makes that manageable and repeatable, that is, a mature process. The process defines the terminology, which project artifacts are used, their lifecycles, the links between artifacts, the metrics, and the reporting.
The lifecycle of primary requirements or enhancements (implementation) reflects how the software product is produced. Distributing requirements across production stages makes the progress of project work visible on the issue, story, and chart boards. Typical stages are Backlog, Analysis, Design, Development, Testing, and Documentation. New useful project artifacts appear at each of these stages.
The lifecycle of business and system requirements, and of test and operational documentation, reflects how ready these project artifacts are. They are used at different stages of software production. Typical stages are New, In progress, Pending approval, Approved, and Done.
The task lifecycle reflects progress on project artifacts and usually includes these stages: New, In progress, Completed. A review stage is sometimes added, where a lead or a senior colleague can check the quality of the completed task.
Stages of different project artifacts are linked (synchronized) by system actions. For example, when tasks are completed, a user requirement can automatically move to the next state. Or a requirement can be marked as implemented when every enhancement for it is done.