You will notice "Account Details" on the pulldown menu under your name has a few interesting options.
This guide will now teach you how to update your personal details in the client area.
It is very important to keep this information current, so that we your hosting company can stay in contact with you firstly and so that your domain registration information will always be up to date.
This guide will assume that you are already logged into WHMCS.
Along the top is the client area menu.
Click on the link called Hello, YourName
This will popup a menu, choose, "Edit Account Details"
This will take you to the personal details page, where you can modify your name, address, and more. If you make any changes, scroll down to the bottom of the page, and click on the Save Changes button.
You can then click on the My Dashboard link, and it will take you to where you can see your updated personal details.
You now know how to update your personal information in the client area