Structured Data and Schema Markup are two crucial aspects of current Search Engine Optimization (SEO) strategies and can significantly affect your website's visibility in Search engine results pages (SERPs). **Structured Data:** In essence, structured data is a standardized way to provide information about a page to search engines. It classifies the page content into types and properties that search engines understand, such as 'Article', 'Product', 'Review', etc. With more specific and categorized information about a page, search engines can deliver more accurate results to users. **Schema Markup:** Schema markup is a manifestation of structured data. It's a semantic vocabulary developed collaboratively by major search engines Google, Bing, Yahoo!, and Yandex, to create a shared data language. By integrating Schema Markup into your HTML, you help these engines understand your content better and offer more detailed results. These tools significantly enhance SEO in several ways: 1. **Rich Snippets and Enhanced SERP Features:** Using structured data and schema markup gives search engines the ability to provide richer search results, including images, reviews, or star ratings. These enrichments (collectively known as 'Rich Snippets') increase the visibility of your site's listing on SERP, making it more appealing and clickable for users. 2. **Improved Crawlability:** By distinctly outlining and categorizing your content, you make it easy for search engines to comprehend your site, thus improving crawlability. 3. **Increase Site Quality:** Search engines, especially Google, consider structured data as a quality indicator. Websites using these techniques are likely to be viewed as reliable and authoritative brands. It can, therefore, indirectly influence rankings and Domain Authority. 4. **Voice Search Optimization:** As voice search gains popularity, structured data allows search engines to pair accurate answers to the voice queries using the details from your site. 5. **Potential for Increased Click-Through Rate (CTR):** Well-implemented structured data can make your website's information more appealing and informationally rich. It means search engine users may be more likely to click on your listing over others, leading to a potential increase in CTR. Remember, structured data and schema markup are not a ranking factor directly. Instead, they improve your website's presentation on the SERP, which can considerably affect click and engagement rates. As a result, they are an essential part of modern SEO strategies – a key to ensuring effective communication between your website and search engines.