Functional testing is a type of software testing that involves verifying the application's functionality against its functional specifications. It comes in various forms, including unit testing, acceptance testing, and integration testing, which can be automated to ensure core functionality and prevent defects from being introduced into production. Investing in functional testing and test automation offers several benefits, including early discovery of major defects, increased confidence with the product, and a reduction in troubleshooting and debugging time. With effective software testing practices, developers can focus on innovation, design, and development of new features, leading to higher quality applications that meet user expectations.