Software requirements specification outline

1. Purpose and scope
   Users, problem, component boundary and exclusions.
2. Context and interfaces
   External systems, inputs, outputs and interface contracts.
3. Functional requirements
   Stable ID, trigger, required behavior and exceptional cases.
4. Quality requirements and constraints
   Performance, safety, security, reliability and resource limits.
5. Assumptions and dependencies
   Operating conditions, external guarantees and open decisions.
6. Verification and acceptance
   Observable criteria, planned methods and evidence references.
7. Governance and change history
   Sources, owners, approval state, revisions and superseded intent.

Guide: https://reqproof.com/topics/software-requirements-specification