Search engines are always crawling the web, looking for new pages to add to their index. The process of discovery can happen in a few different ways. The most common is when a search engine finds a link to a new page while it is crawling an existing website. This can happen when a website owner adds new content or when someone else links to their site. Another way that search engines discover new pages is through sitemaps. Sitemaps are files that contain a list of all the pages on a website, and they provide an easy way for search engines to know about all the content on a site. Finally, search engines can also discover new pages through submissions from webmasters. When a webmaster submits a URL to a search engine, they are telling the search engine that there is new content that it should crawl and index. Regardless of how it happens, discovery is an essential part of how search engines keep their results up-to-date and relevant.