Product Requirements Document (PRD) - A document written by a company that defines the product they make, or requirements for one or more new features of an existing product. A PRD is often created after the marketing requirements document (MRD) has been written and approved by management, and is usually written before (or at least concurrently with) the requirements technical document. It is designed to allow people in the company to understand what the product is supposed to do and how it should work. You can read about this at https://fireart.studio/blog/how-to-write-an-effective-product-requirements-document-prd/ . Everything is detailed.