Your website has a certain “look-and-feel” about it. This represents the agreed “design” elements, fitted into the “purpose” of the various pages. For instance, the “Contact Us” page will look quite different to a page of “General” content or a “Shopping Cart” page. The content on these pages and the way they look-and-feel, is controlled by Page Templates.
Templates are CRITICAL for controlling your site’s look-and feel. When you are editing a page on your site, you will notice that the Editable Content depends on the Template used for that page. If you cannot edit something on a page, there will be a good reason.