How to Change quantity label in woocommerce cart page

You could also use this trick in your functions.php file to replace everything that says “Quantity” on your site:

add_filter('gettext', 'translate_reply');
add_filter('ngettext', 'translate_reply');

function translate_reply($translated) {
$translated = str_ireplace('Quantity', 'New Label', $translated);
return $translated;
}

Just change “New Label” to whatever you want to call it.