If simply interactive is your registrar then you can transfer to somewhere like DH if you want to. I like to keep my domain name registration and hosting mostly separate but I do have one registered here. It is then a matter of updating the domain name servers to point to your current web host. Also you would need to transfer your website’s files to the appropriate directory on the new host. If you are starting from scratch that doesn’t really matter.
DH does not provide apps for web authoring no. If you really want to have control over your website it is an absolute must to learn the language of the web. While you can get by without knowledge of html, css, php, etc it is better for you, as a developer, to learn. There are many free resources on the web for this. I learned everything I know about web design online for free. A good many people use content management systems like Drupal or WordPress to power their sites, including me, and I actually recommend some sort of cms instead of making static pages. However, if you do not know the basics you will be limited to either using free templates or paying for them instead of making/altering templates to your satisfaction.