What is Schema Markup?
Schema markup is a format for presenting search engines with the key details of your content. Schema is developed and managed by Schema.org, which was founded by Google, Microsoft, Yandex, and Yahoo on June 2, 2011.
While search engines can understand a webpage without a Schema markup, the Schema markup provides specific information about the content, allowing them to understand the page better. Search engines also require creators to include Schema markups in their content in order to feature rich results.
While Schema markup and structured data are used interchangeably, structured data is a general name for any data created & stored in a standardized format, and Schema markup is a type of structured data.