Adding Scheme.org, Microformats, and Open Graph to your webste

I've read that adding Scheme.org, Microformats, and Open Graph to a website is a good idea and is now even taken into account by Google when ranking websites.
I don't see any built in support in admin to add this? Is the most practical or only way to add these things is to use an extension?

Also, my understanding is that Google offers a tool that lets you generate Scheme markup, but then that markup has to be added to your pages. ( I assume in the Head part of the page? So it is not visible to visitors)
If you generate your own scheme markup from Google, is there any built-in way in OpenCart admin to insert into page Head? Or would you need to actually manually edit your page templates?

If using Extensions is only or best way, can anyone comments on their results, and perhaps suggest a good extension to use with Opencart 3.x?

Our Google Structured Data extension might help, if offers embedded structured data via JSON-LD containing more details for search engines. It is based on the 'schema.org' standards. It enables Google to present search results as rich snippets.

Having said that, you shouldn't worry too much about it. Google can be like a moving goal post, and the best strategy still is to use relevant and good quality content on your web pages which search engines will pick up.