URL parameters are additional values appended to the end of a URL that modify the content displayed on a webpage. They are commonly used in e-commerce websites for filtering products, sorting search results, or tracking marketing campaigns. While URL parameters can enhance user experience and website functionality, they can also cause indexing issues if not handled properly. Search engines may perceive pages with different URL parameters as separate pages, leading to duplicate content problems and inefficient crawling and indexing. To address URL parameter issues, webmasters should use Google Search Console's URL Parameters tool to specify how search engines should handle specific URL parameters, such as whether they change page content or are used for tracking purposes only. They can also use canonical tags or 301 redirects to consolidate duplicate content variations and improve indexing efficiency.