Hi donnainky,
Perhaps you’re referring to a webmaster? I’m not sure what you read exactly, but usually the admin refers to you as the site owner. Allowing to easily edit settings, permissions and to create and manage content for a website, blog, forum etc.
Do you currently have a website or blog? I recommend WordPress. If you just want a casual site for personal use I would recommend http://wordpress.com/ where they host your site for free.
If you’re looking for something a little more serious for perhaps a small business I would recommend getting your own hosting and domain and host your own CMS WordPress software http://wordpress.org/.
As an admin you can easily login and create new pages very easily similar to how you might create a Word document.
Thanks, Bryan