By default we make use of Google Rich Markup for FAQs so you don't need to worry about adding extra stuff. Rich snippets get added to your dedicated FAQ page.
Google has a nice tool where you can test results of this. You would need to copy paste your dedicated FAQ page URL in their tool.
Google Tool: https://search.google.com/test/rich-results
Example FAQ Page: https://faq-demo-store-theme-one.myshopify.com/a/faq
Or you can simply click on this link which would open results for above demo FAQ page.
Google Search Preview: