href html

<a href="http://example.com" >Link text</a>

<a href="url">link text</a>

<a href="#"><!-- The "#" to be replaced with filename or website address -->Go Somewhere</a>

<a href="link">text</a>

<a href = 'website.com/your/linked/page'>Text in link</a>

Actually href is a html attribute, which is used for passing page url to the a tag.
Example
<a href="url">Click here</a>

<nav>
        <ul>
            <li><a href="index_2.html" 
                title="Accueil">Accueil</a></li>
             <!--ou -pour -->
            <li><a href="../index_2.html" 
                title="Accueil">Accueil</a></li>
            <li>Contact</li>
        </ul>
</nav>

<a href=""></a>

<a href="mailto:[email protected]?subject=subject&[email protected]">mail link</a>

The href attribute specifies the URL of the page the link goes to