Google Structured Data Markup lets you scrap a part of code from the backend of your website. You then mark it up by defining different elements in a dropdown. The tool then creates a marked up code (also known as schema code or structured data) that you can add to the header of your website.
The ‘adding the markup code to your site’s header’ part is where it gets tricky. You could mess up your theme if you don’t know where to put the markup. This is the reason why I recommend using a WordPress rich snippet plugin for the task.