To document clause 4.2 "Understanding the needs and expectations of interested parties" in ISO 14001, organizations have the flexibility to choose the most suitable format based on their specific requirements and context. While documentation is not mandatory, it is common to create a list or register of interested parties and their requirements. This can include:

1. Identifying interested parties relevant to the Environmental Management System (EMS).
2. Gathering and categorizing their needs and expectations.
3. Prioritizing these requirements based on significance and alignment with organizational objectives.
4. Documenting the information in a register or similar documentation.
5. Regularly reviewing and updating the documentation as needs and expectations change.