quickly and easily check the balance on your card without logging into your account! Simply enter your card number and security code, which may be located on either the. check your card balance. Quickly and easily check the balance on your card without logging into your account! Simply enter your card number and security code, which may be located on either the front or back of your card. ready to sign in or register for a health plan account? Find links for unitedhealthcare’s secure sites for members, employers, brokers or…