To help you upsurge towards your business goals, we suggest you to try using a business requirements document. Writing a functional requirements document (frd) is an essential step in the software development process. A functional specification document (fsd), also known as a functional requirements document (frd), is considered by many project management and software. [provide a list of contractual or task level assumptions and/or constraints that are preconditions to preparation of the frd. We’ll delve into the essential components, explore best.