Final answer:
A Warning Order is the document that permits subordinate commanders to prepare for operations as directed by a higher authority and is essential for strategic military planning.
Step-by-step explanation:
The type of document being asked about is a Warning Order. This document is a directive issued by higher authority that allows subordinate commanders to start preparing their supporting plans and orders. It outlines the operations that need to be carried out either simultaneously or one after another. The planning process within military operations is a critical step where strategic decisions are made to ensure the force's readiness and to maintain strategic superiority. The Warning Order is a part of this process, and it enables units to effectively respond to global threats and resource competitions in a controlled and strategic manner.