The key elements of an ISO 14001 EMS are:

Environmental Policy- the environmental policy and the requirements to pursue this policy via objectives, targets, and environmental programs
Planning- the analysis of the environmental aspects of the organization (including its processes, products and services as well as the goods and services used by the organization)
Implementation and operation- implementation and organization of processes to control and improve operational activities that is critical from an environmental perspective (including both products and services of an organization)
Checking and corrective action- checking and corrective action including the monitoring, measurement, and recording of the characteristics and activities that can have a significant impact on the environment