The Project Management Plan Document also known as Project Plan Document or simply Project Plan is a document that contains the strategy for managing the project and the processes related to all areas of the project (scope, cost, schedule, quality, etc.) which are known as Knowledge Areas according to PMI. There are lots of project management processes mentioned in PMBOK® Guide, but determining what processes need to be used based on the needs of the project which is called Tailoring is part of developing the project management plan
The project plan document may include the following sections:
A High level overview of the project
The roles and authority of team members. It represents the executive summary of the Project Management Plan
The scope statement from the Project charter should be used as a starting point with more details about what the project includes and what it does not include (In-Scope and Out-Of-Scope)
A list of the project Milestones (the stop points that helps evaluating the progress of the project). This list includes the milestone name, a description about the milestone, and the date expected.
WBS which consists of Work Packages and WBS Dictionary, which defines these work packages, as well as Schedule Baseline, which is the reference point for managing project progress, are included here.
This section contains all management plans of all project aspects
Identify key resources needed for the project and their times and durations of need.
This section includes the budgeted total of each phase of the project and comments about the cost.
Acceptable levels of quality.
Some space for the project sponsor to sign off the document