[HELP] Looking on how can I redirect all my visitors to a solid URL

hi! I am currently hosting a website, mydomainname.com
Now, I know that spiders and crawlers know that mydomainname.com is different from www.mydomainname.com

Now, I want every visitors of my sites mydomainname.com or www.mydomainname.com to redirect ONLY to: mydomainname.com

Maybe not redirect but just to make their address to mydomainname.com

Now, how can I implement it? Is it in my hosting or in my .htaccess?

Please help.
Thanks in advance and more power.

 

this code in your htaccess should do the job :

 

Thank you very much for your reply. And sorry for giving my gratitude late.

Thank you again.

 

You can even do this in Google Webmaster Tools too. In settings, you can select your preferred domain (with or without www). That way, you can be sure Google will index your homepage the way you want it to!

 

Yes, .htaccess does the trick

 

Yeah, you can do this with .htaccess. You can find more info if you search "canonical url htaccess" on google.