The last stage of software testing is called User Acceptance Testing (UAT), during which end users test the program to ensure it satisfies their requirements and expectations. In contrast to other testing phases (like unit testing or integration testing), UAT is centred on verifying the program from the viewpoint of the actual user, making sure it functions as intended in a real-world situation.
User Acceptance Testing (UAT) aims to verify that the system functions for the user and satisfies the business criteria it was created to fulfil. This step helps find any possible problems or defects that might have gone unnoticed earlier in the development process.