ExpressionEngine is a database-driven application. So to back it up, you need to back up both the individual files on your web server and the database itself.
To back up ExpressionEngine, you need a tool such as phpMyAdmin. If your website is hosted by a website hosting provider, contact them and ask if phpMyAdmin or another tool is installed that will allow you to do MySQL database backups. If necessary, phpMyAdmin can be downloaded from http://www.phpmyadmin.net/. phpMyAdmin is included with local development environments, including WampServer, XAMPP, and MAMP, usually at an address such as http://localhost/phpmyadmin
(all in lower-case).
1. The first step to doing a backup is to clear all the unnecessary data from the database (such as cached templates). Log in to the control panel and select Tools | Data | Clear Caching. Select All caches and click Submit.
3. On the left-hand side, select the ExpressionEngine database...