WordPress by default, supports www or non-www, but not both. However, this can be changed within WordPress at any time to one or the other. Below is a quick outline of how to do this (in the current version):

Updating your WordPress URL:

• Login to your WordPress Dashboard
• Click on "Settings"
• Now, click on "General"
• Modify both of the below settings:

  Blog address (URL)
  WordPress address (URL)

• Upon completion, click "Save Changes"

Well done, you've changed your domain to a www. or non-www. version.