Hi. I'm curious. Is there an app or something that exist in the B.C. module where it'll allow me to add a Google advertisement banner?
There's no app or module inside Business Catalyst to achieve this. I assume Google will provide you with HTML code you simply insert on the page you want the add to display on.
Create a Content holder, put the code you get into there and insert it as a module where you need it.
This way if you have it in multiple Templates for example if you ever need to update or change the code it will change it throughout your website.