How do I enable URL-Rewrite?

Add a .htaccess file in the same folder where the index.php file is located with the following contents-

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?ng=$1 [L,QSA]

Now, using phpMyAdmin or any other database management tool, run this SQL command-

UPDATE sys_appconfig SET value=1 WHERE setting='url_rewrite';