function custom_loginlogo() {
echo '<style type="text/css">
h1 a {background-image: url('.get_bloginfo('template_directory').'/images/login_logo.png) !important; }
</style>';
}
add_action('login_head', 'custom_loginlogo');


<?php
add_filter( 'login_headerurl', 'custom_loginlogo_url' );
function custom_loginlogo_url($url) {
	return 'http://www.wpbeginner.com';
}
?>

Wordpress - Change Login logo and login LINK

PHP