Yes, all clients can access their website with and without the www. In other words, you can access your website at www.yourdomain.com or just yourdomain.com, both of which are the same website. While this may seem somewhat unimportant, many would be surprised at how many people exclude the www and how many providers do not provide this service. Offering both options ensure you do not loose any visitors to your website as a result of this example of a common mistake.