This tutorial will help you understand the four different user types of Joomla and what each can do.
A Joomla site is just an empty shell without an active user base. The first user group is the Registered group. This group does not have any kind of access to write, edit, or publish articles on a Joomla site.
Second, we have the Author group. Authors are allowed to submit content to a Joomla site. They can edit their own articles, but no one else's. They cannot publish content. Typically, when logged in as an author, you will see links appear, that say things such as Submit an article, Submit a Web Link, etc.The third group is called Editor. Editors can edit other people's content as well as their own. They still can't publish anything however. You will now see an edit icon (paper and pencil) next to each article.
The last group is Publisher. There is now an option visible that indicates published, yes or no. Except for that, publisher is no different from an Editor. Every Joomla content item must be published before it is visile to everyone, so Publishers get the final say for content posted to a site.
This completes this tutorial. You now know the four user groups of Joomla.