.htaccess

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule .* index.php/$1 [PT,L]
Or

Options +FollowSymLinks
Options -Indexes
DirectoryIndex index.php
RewriteEngine on
RewriteCond $1 !^(index\.php|images|robots\.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L,QSA]