Heading Tags (h1, h2, h3...) are HTML programming resources used to
highlight titles and subtitles on a page.
When search engines (such as Google) crawl the page, the heading tags
facilitate reading, understanding and even content indexing.
Heading tags are used to define the hierarchy and structure of a page.
When you have great heading tags, it can make a big difference to SEO
performance.
In this case, the HTML code is telling Google that "This is an h1" is
more important than "This is an h2".
The "strong" tag makes makes the font bold.
This is an emphasized textThe content inside the "em" tag is normally displayed in italic.