During requirements modeling, systems developers must identify and describe all system requirements.

In engineering, a requirement is a singular documented need of what a particular product or service will be or perform. It is a statement that identifies a necessary attribute, capability, characteristic, or quality of a system in order for it to have value and utility to a user.

Requirements are used as inputs into the Design phase of technology product development. Requirements are an important input into the verification process since tests are required to trace back to specific requirements.

Fact$-$finding $($gathering information$)$ involves answering $5$ questions: Who, What, Where, When and How. The common fact$-$finding techniques are interviews, document review, observation, sampling, research, surveys, and questionnaires.

A collection of requirements defines the characteristics or features of the desired system. A 'good' list of requirements avoids saying HOW the system will implement the requirements, leaving such decisions to the system designer. Describing how the system will be implemented may be known as "implementation bias" or "solution engineering".

Your technology solution will major Functions that can be completed by the user. For example, an online banking application provides the user to deposit checks, transfer money from one account to another, check balance, and open a new account.

Each function requires business requirements that must be met for the function to work according to the user's expectations.