ISO 14004:2016 5.3: Organizational roles, responsibilities and authorities
Guidance: top management should appoint a representative or function with enough authority, competence, awareness and resources to make sure the system is established, implemented and maintained at all applicable levels, and to report to top management on the system including environmental performance and opportunities for improvement; these duties can be combined with other roles. Responsibilities and authorities of everyone whose work affects the system should be defined and communicated, are not confined to the environmental function (design, procurement, engineering and quality all carry them), should be matched by resources, and should be reviewed when the organization's structure changes. Typical allocations run from the board setting direction and the CEO owning the policy to designers considering aspects, purchasers setting supplier criteria, all managers assuring compliance and everyone conforming to the system.
This control maps to 29 controls across 22 other frameworks. If you already hold one of them, the evidence you collected for it is the starting point here rather than new work.