How to change the label of wordpress login screen?

Is there any hook to modify label of wordpress login screen?

Yes you can change the wordpress login screen label like username of email address to only email address as per your choice. We have login_head action and gettext filter using combination of these hook we can modify the label. Please follow the below example for better understanding: 


//Modify login label
function login_screen() {
    add_filter( 'gettext', 'modify_label', 20, 3 );
    function modify_label( $translated_text, $text, $domain )
        if ($text === 'Username or Email Address')
            $translated_text = 'Email Address';
        return $translated_text;
add_action( 'login_head', 'login_screen' );


Paste the above code in functions.php file of wordpress and it will work fine.