Structured data markup is a way of making web content more understandable to search engines. It involves adding special tags, or labels, to web pages that describe the content contained in each section. This helps search engines better understand what the page is about and categorize it appropriately when displaying results for users. Structured data markup can also be used to display rich snippets on SERPs, which are small pieces of information such as reviews or ratings that appear next to search engine results. By adding this extra information, it can help draw attention to your site and make it stand out from other competitors. Structured data markup is an important tool for improving SEO and increasing visibility on the web.