A Test Plan is a document that outlines the strategy and approach for testing a software application. It includes details such as the scope of testing, objectives, resources required, and the schedule. The plan serves as a roadmap for the testing process, ensuring that all necessary aspects are covered and that the testing team is aligned on goals. In a Test Plan, various elements are defined, including the types of tests to be conducted, such as unit testing, integration testing, and user acceptance testing. It also identifies the roles and responsibilities of team members, tools to be used, and criteria for success, helping to ensure a thorough and organized testing process.