PHP code inside functions.php to load facivon.ico file as your website favicon

favicon-function.php

//add a favicon for your WordPress website
function blog_favicon() {

//this will load the favicon from the root directory of your blog
//	echo '<link rel="Shortcut Icon" type="image/x-icon" href="'.get_bloginfo('wpurl').'/favicon.ico" />';

//this will load the favicon from the root directory of your theme
	echo '<link rel="Shortcut Icon" type="image/x-icon" href="'.get_bloginfo('stylesheet_directory').'/favicon.ico" />' . "\n";

}
add_action('wp_head', 'blog_favicon');