how to section element in css code example

Example 1: section tag in html

Section tag defines the section of documents such as chapters, headers, footers
or any other sections. The section tag divides the content into section and 
subsections. ... Section tag grouped the generic block of related contents.

Example 2: how to use section tag in bootstrap

<section id="header"> Name of section
	<div class="container">
		<div class="row">
			<div class="col-xs-12"></div>
		</div>
	</div> 
</section>

<section id="main-content"> Name of section
	<div class="container">
		<div class="row">
			<div class="col-xs-6"></div>
			<div class="col-xs-6"></div>
		</div>
	</div> 
</section>

<section id="footer"> Name of section
	<div class="container-fluid">
		<div class="row">
			<div class="col-xs-4"></div>
			<div class="col-xs-4"></div>
			<div class="col-xs-4"></div>
		</div>
	</div> 
</section>