“What’s the difference?”, you may ask. Both these elements are used for sectioning a content, and yes, they can definitely be used interchangeably. It’s a matter of in which situation. HTML4 offered only one type of container element, which is <div>. While this is still used in HTML5, HTML5 provided us with <section> and <article> in a way to replace <div>. See this salesforce training in India webpage for a good web page design.

The <section> and <article> elements are conceptually similar and interchangeable. To decide which of these you should choose, take note of the following:

An article is intended to be independently distributable or reusable.
A section is a thematic grouping of content.
Code:
<section>
  <p>Top Stories</p>
  <section>
    <p>News</p>
    <article>Story 1</article>
    <article>Story 2</article>
    <article>Story 3</article>
  </section>
  <section>
    <p>Sport</p>
    <article>Story 1</article>
    <article>Story 2</article>
    <article>Story 3</article>
  </section>
</section>