Schema markup is actually a Specific code that is added into the Websites inside a standardized way in order to describe its this means for the computer systems. As it has standardized framework, it can be also called structured data, and since it always appears as snippet of code, it's https://addons.prestashop.com/ru/seo-natural-search-engine-optimization/31857--rich-snippets-json-ld-opengraph-seo.html