One question that is often asked is, “Where does Joomla keep the articles, pictures, links, and so on that I put into it?”
The short answer is “different places.” Joomla keeps information from the articles and pages that you create in two places. First of all, the text of the articles are keep as records in a database. All Joomla sites use a database to keep a lot of the information that helps manager the site, and your articles (and links, and contact items, etc.) are in that database. Generally, the database is provided by a database called mySQL that is provided as part of your web hosting service. Joomla manages getting articles in and out of this for you automatically.
So, you will not find a “file” on your website that contains the text of your articles. It is stored away in the Joomla mySQL database.
Now, photos, icons, graphics, and things like that are not stored in the database. They are actually stored as files in the file system of your Joomla installation.
Different types of files are stored in different locations. Generally, photos, graphics, and icons that you add to your site are stored in the /images/stories folder (and other sub-folders under that which you may create).
Other Joomla extensions may store their data differently. Many of them use the mySQL database, some use individual files put in various folders, and many use both.
So, if you decide to backup your Joomla based website (always a good idea) or move it to another location, you have to move both the files that make up your site, and the information in the database. Now, if you are moving your site from one folder on a server to another folder on the same server, then generally you just have to move the Joomla files to the new folder.
But moving from one server to another requires you to move both the files of your Joomla site, and the information in the database.
For more information on moving your Joomla site, see the article on that topic.