An image forming apparatus includes a communication interface unit to perform communication with a cloud server that provides an application service; a user interface unit to display a screen and receive a user input; a storage unit to store a database that corresponds to an application that is installed in the image forming apparatus; an image forming operation performing unit to perform an image forming operation; and a control unit that stores user log-in information in the database that corresponds to the application, so as to match the user log-in information with a user account for the image forming apparatus, and manages a log-in to a user account for the application by using the stored user log-in information.