quantity input box on category page

That is actually more of a question for our WooCommerce Thumbnail Input Quantities plugin as that adds the input box to the category / shop / any product thumbnail page.

Either way however, we don’t support that feature, but if you familier with editing your functions.php file you can insert the below code to get your desired effect.

add_filter('woocommerce_loop_add_to_cart_link', 'wpbo_add_message', 10, 2 );

function wpbo_add_message( $text = null, $product = null ) {
	$message = '<span>Minimum Order: 12</span>' . $text;
	return $message;
}

This will add your $message, to just before the input box.

Thanks and enjoy the plugins!