A system comprising an electronic device comprising: a housing accommodating a display; a processor; and a secure memory configured to store payment information and user authentication information; wherein the system further comprises a user authentication device, which is one of: - integrally formed with the display; - mounted at the housing; and - connectable wirelessly to the electronic device, and wherein the user authentication device is configured to obtain user authentication information from the user; wherein the processor is functionally connected with the secure memory and configured to perform authentication based on stored user authentication information and obtained user authentication information and control a multiple payment operation including a method of payment using near field communication, NFC, and a method of payment using magnetic security transmit, MST; wherein the processor is further configured to control a signal processing information to be output as one screen interface when user authentication information obtained by the user authentication device is valid, the system being characterized in that the secure memory is configured to store payment information based on the method of payment using NFC and on the method of payment using MST, the signal processing information comprises a: signal processing information according to the method of payment using NFC and a signal processing information according to the method of payment using MST, and in that the processor is further configured to: - display at least one of an object for instructing a signal transmission start guide for payment processing, an object associated with a signal transmission direction according to the method of payment using NFC, or an object associated with a signal transmission direction according to the method of payment using MST, - operate the method of payment using NFC and the method of payment using MST alternately, and - differently display the object associated with a signal transmission direction according to the method of payment using NFC and the object associated with a signal transmission direction according to the method of payment using MST. a housing accommodating a display; a processor; and a secure memory configured to store payment information and user authentication information; wherein the system further comprises a user authentication device, which is one of: - integrally formed with the display; - mounted at the housing; and - connectable wirelessly to the electronic device, and - integrally formed with the display; - mounted at the housing; and - connectable wirelessly to the electronic device, and wherein the user authentication device is configured to obtain user authentication information from the user; wherein the processor is functionally connected with the secure memory and configured to perform authentication based on stored user authentication information and obtained user authentication information and control a multiple payment operation including a method of payment using near field communication, NFC, and a method of payment using magnetic security transmit, MST; wherein the processor is further configured to control a signal processing information to be output as one screen interface when user authentication information obtained by the user authentication device is valid, the system being characterized in that the secure memory is configured to store payment information based on the method of payment using NFC and on the method of payment using MST, the signal processing information comprises a: signal processing information according to the method of payment using NFC and a signal processing information according to the method of payment using MST, and in that the processor is further configured to: - display at least one of an object for instructing a signal transmission start guide for payment processing, an object associated with a signal transmission direction according to the method of payment using NFC, or an object associated with a signal transmission direction according to the method of payment using MST, - operate the method of payment using NFC and the method of payment using MST alternately, and - differently display the object associated with a signal transmission direction according to the method of payment using NFC and the object associated with a signal transmission direction according to the method of payment using MST. - display at least one of an object for instructing a signal transmission start guide for payment processing, an object associated with a signal transmission direction according to the method of payment using NFC, or an object associated with a signal transmission direction according to the method of payment using MST, - operate the method of payment using NFC and the method of payment using MST alternately, and - differently display the object associated with a signal transmission direction according to the method of payment using NFC and the object associated with a signal transmission direction according to the method of payment using MST.