Where can I add <script type = 'application / ld + json'> to better reference my site's ads

I filled all the fields: Heading H1, Meta description, Meta keyword, but the SEO of my site is not good.

When I test my site on: https://search.google.com/structured-data/testing-tool
I get no results

Do Flynax plans to improve the SEO of sites with structured data?

This is the future of search tools on the web

Thanks,

Marc