In this phase, it is necessary to obtain defined problems from our stakeholders and develop design parameters, or functional requirements, which will be categorized into constraints and objectives. Constraints are design priorities in which these specifications have to be included in our final project. Objectives are tentative goals that we strive to complete, however, their metrics and target values will be adjusted as we learn more. Both of these constraints and objectives are brought to us through surveys, interviews, and research, and they will later be categorized again by metrics, specifications, and priority. These are located within their respective pages and will also include detailed descriptions of the functional requirement, the specifications, and why the team decided on them.
https://www.perforce.com/blog/alm/what-are-non-functional-requirements-examples