Project plan
A project plan is a series of structured tasks, objectives, and schedule to complete a desired outcome, according to a project manager's designs and purpose. According to the Project Management Body of Knowledge (PMBOK), a project plan is "...a formal, approved document used to guide both project execution and project control. The primary uses of the project plan are to document planning assumptions and decisions, facilitate communication among project stakeholders, and document approved scope, cost, and schedule baselines. A project plan may be summarized or detailed."
The latest edition of the PMBOK (v6) uses the term project charter to refer to the contract that the project sponsor and project manager use to agree on the initial vision of the project (scope, baseline, resources, objectives, etc.) at a high level. In the PMI methodology described in the PMBOK v5, the project charter and the project management plan are the two most important documents for describing a project during the initiation and planning phases.
The project manager creates the project management plan following input from the project team and key project stakeholders. The plan should be agreed and approved by at least the project team and its key stakeholders.
Many project management processes are mentioned in PMBOK Guide, but determining which processes need to be used based on the needs of the project, which is called "tailoring", is part of developing the project management plan.