The goal of Manual Testing is to ensure that the application is error free and it is working in conformance to the specified functional requirements. Test Suites or cases ,are designed during the testing phase and should have 100% test coverage.
It also makes sure that reported defects are fixed by developers and re-testing has been performed by testers on the fixed defects. Basically, this testing checks the quality of the system and delivers bug-free product to the customer.