by default it’s accessible with http://server_IP/owncloud even when on disk ownCloud is located in /var/www/owncloud.
In /etc/apache2/sites-available, there should be a file owncloud.conf
In /etc/apache2/sites-enable, there should be a symbolic link to the above file.
owncloud.conf from /etc/apache2/sites-available
will contain an
Alias /owncloud /var/www/owncloud which tells apache2 service where to look for when you are trying to connect on http://server_ip/owncloud or http://localhost/owncloud (last only from the server available where owncloud is directly installed)
if you want to access your owncloud server you should modify /var/www/owncloud/config/config.php in trusted_domains section and add localhost.
localhost will have IP: 127.0.0.1 which mean you can only access it from that server only.
And… you should not move your ownCloud as the DB is already configured with that location.