According to ISO 9001:2015 it is not mandatory to keep documented evidence of how an organization has considered clauses 4.1 and 4.2. However, most organizations decide, and I recommend it too, to document their external and internal issues and interested parties. Normally, this can be documented with the minutes of a meeting where the topic was addressed, and the conclusions and decisions are recorded. Where there is no documented evidence, I try to use corroboration as a technique during my audits. Asking several people, at different levels in the organization hierarchy and in different places, at different times, the same question and compare their responses.