I have installed froxlor and configured all the settings from settings panel

I created a customer domain and vhost file has got created automatically in sites-enabled, however, 

the file name looks like this 35_froxlor_normal_vhost_domainname.conf, but vhost sites enabled conf file name will look like domainname.conf. So we can enable the site with the command sudo a2ensite domainname. 

(have replaced actual domain name)

Do I need to do that manually - copy the file 35_froxlor_normal_vhost_domainname.conf to domainname.conf and enable a2ensite?

The files are usually and per default created in sites-enabled. There is no need for a2ensite or anything manual.

But the site is not pointing to the directory specified in vhost file created. 

I have pointed A record of the server and when I tried to access the website it shows default index page of the server and not the path specified in the vhosts file(/var/www/customers/webs/domainname)

 

This can have multiple reasons. Be sure you add the ipv6 address to froxlor in case your server also listens on ipv6 

My server listens to ipv6 where to add the ipv6 address in froxlor?

Login as admin -> IPs/ports

 

And don't forget to assign it to the domains