Software testing is a process of evaluating software to identify defects and ensure it meets requirements. There are different levels of testing like unit, integration, and system testing. Various techniques are used like black-box, white-box, and gray-box testing. Effective testing requires creating test cases using techniques like equivalence partitioning and boundary value analysis. Tests are executed, defects are tracked, and documentation is maintained throughout the testing process. Communication between testers and other teams is important for testing success.