How to enable Search Engine Friendly URLs in Magento
To enable Search Engine Friendly URLs in Magento, you have to log in to the Magento administration area and click on the Configuration button. Under the System navigation menu, switch to Web page from the sub-navigation panel on the left.
When the page loads, you will see blue lines which represent closed options tablets. Click on the Search Engines Optimization tab and turn on the Use Web Server Rewrites (mark as Yes). Click on the Save Config button and your Magento SEF URLs will be enabled.