According to IIA guidance, the internal audit charter should formally document the nature of consulting services provided by the internal audit activity. This ensures that the scope and extent of consulting services are clearly defined and understood, helping to manage expectations and clarify the role of the internal audit function in such activities.References: IIA's International Professional Practices Framework (IPPF) - specifically, the attribute standards relating to the internal audit charter which should outline the nature of consulting services among other fundamental roles and responsibilities.