Structured data is a standardized markup code added to the HTML to definine the various content elements on webpages. Google uses the markup to recognize and display relevant content such as recipe ingredients, cooking time, and cooking temperature (for recipes) in SERP features such as rich cards.
The Schema Markup Generator allows you to create the code needed to produce rich results on the SERP.
Google’s Structured Data Markup Helper is a tool that assists webmasters to create structured data markup code to add to their web pages.
For more information