Robots meta directives (sometimes called “meta tags”) are pieces of code that provide crawlers instructions for how to crawl or index web page content. Whereas robots.txt file directives give bots suggestions for how to crawl a website's pages, robots meta directives provide more firm instructions on how to crawl and index a page's content.
HTML is the underlying code used to create web pages. Search engines can pick up ranking signals from specific HTML elements. Below are some of the most important HTML elements to achieve SEO success.