In earlier HTML there was no element for article, we used to write a css-class that can be used for article, though there was some article tag in schema.org, now in HTML5 there is a <article> tag, and we don’t need to write any additional class, though still we can enhance the look of the tag using css.
The <article> tag indicates a self-sufficient piece of content which can be distributed with any other websites and social media platforms.
We can use this <article> element for our blog post another way to tell search engine about the new piece of information to be crawled first.
Though Article tag definition in schema.org remain the first choice
<article> This is an example of article tag in html5 </article>
HTML5 is very demmanding skill for Web Developer or Web Designer