Generating Extent Reports in Selenium involves using an open-source library that provides enhanced reporting features beyond the built-in reports available in frameworks like TestNG and JUnit. Extent Reports offer customizable, detailed test case information, including graphical data visualization and integration with various test automation frameworks. To create these reports, testers need to configure the ExtentHtmlReporter, ExtentReports, and ExtentTest classes, which allow for the customization of the report's appearance and content, such as attaching screenshots and setting themes. Test execution can be done in parallel, significantly reducing execution time by utilizing cloud-based platforms like LambdaTest. This process is supported by tools like Jenkins for continuous integration, making it easier to manage and share test execution summaries with stakeholders. Extent Reports are valued in the automation community for their ability to provide a comprehensive and visually appealing summary of tests, aiding in the analysis of test results and decision-making processes.