Requirements are categorized into four types as follows:  Technical requirements: These requirements define the technicalities of a software system.   Functional requirements: These requirements determine the features and functionalities of the software. It defines how the system must operate as per the viewpoint of the end-user.   Operational requirements: These requirements represent the background activities required to be performed to keep the system functioning.  Transitional requirements: These requirements mention the steps of smooth implementation of the system.