If you are using WHMCS v6 or higher it is possible to show a widget directly at the client area.
This means that you do not have to explain to the customer where he can find the pin, because he can generate a pin on every page.
At the module configuration it is possible to define exactly on which sites the widget should be visible.
Default values are: "addcontact,changepw,contacts,creditcard,details,emails,security,services,,"