Schema Markup is nothing but a snippet of code that is generally added to the HTML code of a web page in order to give away information about your page and the purpose of the page to search engines. Specific values are assigned to a word which makes it easier for search engines to carry out indexing of the content and categorize it accordingly. In other words, you are not leaving anything up to the search engine to find out as whatever information it might need about your page is provided by the schema markup itself.