Test plan document is prepared by the test lead, it contains the contents like introduction, objectives, test strategy, scope, test items, program modules user procedures, features to be tested features not to tested approach, pass or fail criteria, testing process, test deliverable, testing, tasks, responsibilities,resources,schedule, environmental requirements, risks & contingencies, change management procedures, plan approvals, etc all these things help a test manager understand the testing he should do & what he should follow for testing that particular project.