Documenting the functional requirements provides several important benefits to the organisation and to the process of developing a solution. An frd defines the specific functions and features that the. A functional specification document (fsd), also known as a functional requirements document (frd), is considered by many project management and software. It provides a single reliable source of. A functional requirements document (frd)—also known as a functional requirements specification, functional specification, or functional specification document—is a more.