Scope modelling is the technique used to identify the elements and boundaries of the requirements architecture. This technique involves defining what is included within the project or initiative and what is outside its boundaries. Scope modelling helps in clarifying the scope of the work, the features and functions that are to be included in the solution, and any constraints or limitations that should be considered. It provides a structured approach to understanding the overall context and limits of the change being proposed, ensuring that stakeholders have a common understanding of what the initiative aims to achieve and what it does not cover.