About the terminology:
- A requirement expresses a need that the system has to fulfil, in principle independently of the solution that will be chosen. Example: "The system shall allow only valid contract types to be entered".
- A feature is something that the system offers: it's part of the solution, regardless of the underlying needs. Example: "A drop-down list provides a choice between possible contract types". May be this feature addresses a requirement, maybe not.
- An objective, is something that business actors are expected to achieve. It's "why" people are doing things and have requirements. An objective of a clerk in a law firm, could for example be to prepare contracts. If the software shall help in this objective, it will have to fulfill a requirement, and it can provide some features to facilitate the tasks needed to fulfill the objective.