Even in agile you should use a Project Initiation Document

When you think of Project Initiation Documents, or PIDs, you think of Prince2 project management, and the need to document a variety of factors in a large scale project. You don’t think of using a PID when you’re delivering in an agile methodology, but you probably should.

What is a Project Initiation Document (PID)?

A PID is seen as one of the most important pieces of documentation in project management, as it forms the foundation of the reasoning behind the commencement of a project.