Hi,
Thank you for your message.
In this case I believe that you dont need macro at all. It seems like you want to hardcode the query string value because while you are sending the e-mail you dont have the context of that page available and the system cannot have idea which page do you mean.
Anyway you can create a custom macro which can return dynamically your link with query string based on your own conditions. Creating macros is easily, please checkout this article
Kind regards,
Richard Sustek