A project charter is a formal, typically short document that describes your project in its entirety — including what the objectives are, how it will be carried out, and who the stakeholders are. It is a crucial ingredient in planning the project because it is used throughout the project lifecycle.
The Project manager creates the project management plan following inputs from the project team and the key stakeholders. A Project management plan is a formal, approved document that defines how the project is executed, monitored, and controlled. It may be a summary or a detailed document and may include baselines, subsidiary management plans, and other planning documents. This document is used to define the approach the project team takes to deliver the intended project management scope of the project.
