The first step of the configuration process is to decide whether you want to point your Kartra integration (and thus your Kartra Pages, your Kartra checkouts, etc) to www.Domain.com or to SubDomain.Domain.com.
Some users might prefer to keep their different pages organized around subdomains. For example:
Imagine you sell different 3 products through your website, and thus your have 3 sales page and 3 checkout pages:
Well, instead you might prefer to use a separate subdomain for your sales pages, and another one for your checkouts pages:
It’s entirely optional, but some users argue that it helps keeping your site URL structure cleaner and, according to some experts, it yields some SEO benefits as well.