Oh found it :). For anyone, who had the same issue:
You just have to enter the code into the <head>-Section in the Theme-Header (header.php)-Template
<head>
<meta name=”verification” content=”a496ea…” />
<?php
/**
* catchresponsive_before_wp_head hook
*
* @hooked catchresponsive_head – 10
*
*/
do_action( ‘catchresponsive_before_wp_head’ );
wp_head(); ?>
</head>