The most common types of requirement which a Business analyst is interested would be the following −

Business Requirements        

Business requirements are the critical activities of an enterprise that must be performed to meet the organizational objectives while remaining solution independent. A business requirements document (BRD) details the business solution for a project including the documentation of customer needs and expectations.

User Requirements

User requirements should specify the specific requirements which the user expects/wants from software to be constructed from the software project. A user requirement should be Verifiable, Clear and concise, Complete, Consistent, Traceable, Viable.

The user requirements document (URD) or user requirements specification is a document usually used in software engineering that specifies what the user expects the software to be able to do.

System Requirements

System requirements deal with defining software resources requirements and prerequisites that needs to be installed on a computer to provide optimal functioning of an application.

Functional Requirements

Functional requirements capture and specify specific intended behavior of the system being developed. They define things such as system calculations, data manipulation and processing, user interface and interaction with the application, and other specific functionality that show how user requirements are satisfied. Assign a unique ID number to each requirement.

Non-Functional Requirements

Non-functional requirement is the one which specifies criteria that can be used to judge the operation of a system rather than specific behaviors. System architecture speaks on the plan for implementing non-functional requirements.

Non-functional requirements speak on how the system should look like or it can be mentioned like “system shall be”. Non-functional requirements are called as qualities of the system.

Transition Requirements

Transition Requirements describe capabilities that the solution must fulfill in order to facilitate transition from the current state of the enterprise to a desired future state, but that will not be needed once that transition is complete.

They are differentiated from other requirements types, because they are always temporary in nature and because they cannot be developed until both an existing and new solution is defined. They typically cover data conversion from existing systems, skill gaps that must be addressed, and other related changes to reach the desired future state. They are developed and defined through solution assessment and validation.