A Manual Testing Developer performs tests on software manually to identify any bugs or issues. This involves creating test cases, which are scenarios that simulate user interaction with the software, and documenting the results. They validate functionalities, usability, and consistency of the software, checking that it behaves as expected under different conditions. They also identify any areas of improvement or modification. They work closely with the software development team to ensure that all issues are addressed before the final product is released. Manual testing is critical for ensuring software quality, reliability, and optimal user experience.