Get and insert order email address to the PHP template inside HTML text

I broke my head trying to solve the following case. I have a WooCommerce admin-new-order.php PHP template I want to customize. All I want is to add the order email address to the top of the email body inside the custom URL. I’ll explain more detailed below:

I have the <a href="" target="_blank"></a> URL and I want to add this URL to the top of the PHP template.

I need to get the customer email address and insert it inside the URL so the URL will transform into (as an example):

I guess I need to try to code something like that, but unfortunately I can’t get of how to insert PHP here instead of demo email address:

I would appreciate any help with this one.