Usability Testing: Enhance designs by testing the application for all user types, identifying problems and confusion in user experience, and ensuring a user-friendly interface and optimal usability. System Testing: Verify the system\'s compliance with specific requirements, assessing its overall functionality and performance to ensure it meets predetermined standards. Regression Testing: Re-run tests to verify that the application remains fully functional even after changes in the program or code, preventing the introduction of new issues during the development lifecycle.