Documenting clause 4.2 "Understanding the Needs and Expectations of Interested Parties" is not mandatory according to ISO 9001. However, organizations can choose to create documents such as a List of Interested Parties and their requirements or a Procedure for Determining the Context of the Organization and Interested Parties to provide evidence of compliance. The most effective way to meet the requirements is through interviews and maintaining records or registers of interested parties and their needs and expectations.