Many of the wordpress themes are having options in admin panel for uploading and changing the favicon image. But if we want to make a custom favicon image or we do not have any option in theme then we can create a custom favicon for every wordpress site.

We can add this identity by adding the favicon code in wordpress theme's header.php file, or we can make this by adding the following code in your functions.php file.

/ / custom favicon image
    function blog_favicon() {
    echo '<link rel="Shortcut Icon" type="image/x-icon" href="'.get_bloginfo('wpurl').'http://xyz.com/favicon.ico" />'; // path of favicon image
    }
    add_action('wp_head', 'blog_favicon');

After adding just upload the .ico file in the your wordpress site. After uploading , you can replace the path of favicon image in functions.php.

Thanks