Test Documentation refers to the collection of documents that outline the testing process for a software application. It includes various types of documents such as test plans, test cases, and test reports. These documents help ensure that the software meets its requirements and functions correctly before it is released. Effective test documentation serves as a guide for testers, providing clear instructions on what to test and how to evaluate the results. It also facilitates communication among team members and stakeholders, ensuring everyone is aligned on testing objectives and outcomes.