The rapid growth of the mobile app industry, fueled by the widespread use of smartphones, emphasizes the importance of Mobile App Usability Testing to ensure app success and user satisfaction. With the projected expansion of the global mobile application market, it becomes crucial to address usability issues to minimize user churn and enhance customer engagement. Usability Testing evaluates an app's user-friendliness and ensures it meets the end-user's needs across various devices and operating systems. The testing process involves real users to gather feedback, identify design inconsistencies, and discover user preferences, thus enabling developers to make necessary UI adjustments. Different types of usability testing, such as moderated, unmoderated, lab, guerilla, and contextual inquiry, offer diverse insights into user interactions, though each has its own challenges, including high costs and manual efforts. Platforms like LambdaTest facilitate usability testing by providing a real device cloud environment, allowing comprehensive testing across numerous real devices without the need for physical device setups. Incorporating best practices, such as selecting the right audience and testing on real devices, can significantly improve an app's performance and user experience.