Hey All, what the major effect if a website is indexed in Google without www. how much it can affect for ranking.
It doesn't really matter whether you use www. or have your site indexed without it. However you should decide on which you want because if you have both search engines may think you are duplicating web pages and you could be penalised in ranking. If for example your site is anysite(dot)com and you want google to read it as www(dot)anysite(dot)com you should redirect anysite(dot)com to www(dot)anysite(dot)com
Are your both (www and non www) versions of websites got indexed? If yes, then it will raise duplicate content issue. What to do? - Set up a 301 redirect to preferred domain of your website - Set your preferred domain in Google webmaster tools - Use canonical tags
You may have the option to action 301 redirects in your cpanel, otherwise you could just ask your web hosting service to do it for you if they are one of the helpful ones.