An ambulance service cannot wait until an emergency to discover whether someone happens to have a vehicle and a trained crew available. It plans staffing, equipment, and coverage in advance. Planning brings separate contributions into a common account of what needs to happen.
At larger scales, economic planning attempts to reconcile production with expected needs and available resources. Decisions may be concentrated in an authority or developed through repeated exchanges among workplaces, communities, and consumer bodies.
A plan has to learn
The hard part is not producing a document. Conditions change, local knowledge is incomplete, and people have reasons to describe their needs or capacities strategically. A manager may request extra supplies because shortages are costly, while another understates what their team could deliver to avoid a demanding target.
A useful planning process needs ways to surface those differences and revise commitments. Local discretion can absorb unexpected events, but makes the overall plan less exact. Strong central control can maintain priorities while missing circumstances that people on the ground understand better.
Planning also works alongside exchange: a hospital can plan staffing while buying equipment from suppliers. The important distinction is which decisions are coordinated by explicit commitments and which are left to other mechanisms, not whether an organization has a plan at all.