A CMS allows you to edit, publish and maintain your website from a central interface. My favourite CMS is WordPress. 25.9% of the websites online today where build using WordPress.
I highly recommend you use WordPress as your CMS and put it on your own hosting account. Using WordPress on your own hosting account leaves you with the most control over your website. And as your business grows you?re going to want the ability to grow your website without having to completely rebuild it on another platform.