Go to the Administration Panel and login using your username and password, which must have permission to edit Articles.
Navigate to an article either via Site/Control Panel/Article Manager or Content/Article Manager. Find the page you want to edit. As the number of articles on your site grows, use the search filters and drop down menus to narrow the search.
The editing screen appears when the article is opened.
Scroll down the screen to see the full extent of the editor.
When you have done some editing, click on Save or Save & Close. The Close button reverts to the previous information if you do not click on Save first.
When you Save & Close or Close, you are returned to the Article Manager.
To login to Joomla 3 and access your administrative panel, you need to open your browser and navigate to http://mydomain.com/administrator. On this page, you will find a login screen, where you need to enter the username and password you've chosen during the Joomla 3 installation process.