You should get a quarterly statement from the company you invest with. If you haven't received one recently, check with your HR department and they should be able to point you in the right direction.
I agree with Michael regarding the physical account statement. But if you have an old statement you should be able to call directly to the custodian and get current account information and request access via your computer or smart phone. Access to any financial account today should be easy to establish, maintain and monitor.
I am not sure if this applies to your situation, but if you move and change addresses it is your personal responsibility to notify the financial institution or custodian and any former employers (to get your w-2). So please stay connected!