This <nav> tag is use to define a block of navigation link in a same document or
in another document.
In general way we can say it provides more navigation link at a same document.
Let's understand this by the following example:
<p> This is an example of nav tag. </p>
<nav>
<a href="#"> Home </a>
<a href="#"> About Us </a>
<a href="#"> Courses </a>
<a href="#"> Blogs </a>
</nav>
