it is called as User Acceptance Testing ,User acceptance testing (UAT) is the last phase of the software testing process. During UAT, actual software users test the software to make sure it can handle required tasks in real-world scenarios, according to specifications. UAT is one of the final and critical software project procedures that must occur before newly developed software is rolled out to the market.User acceptance testing (UAT), otherwise known as Beta, Application, or End-User Testing, is often considered the last phase in the web development process, the one before final installation of the software on the client site, or final distribution of it.