Disclosed are an electronic device and a method. The electronic device includes a display, a communication module and a processor. The processor implements the method, including displaying an execution screen of a message application, receiving a first input signal for selecting identification information about content from transmission through the message application to an external device, determining, responsive to the reception of the first input signal, the number of segments into which the content is to be segmented, based on the size of the content and the maximum attachment size of the message application, displaying at least one thumbnail representing the content and at least one indicator including information about the segmentation; receiving a second input signal requesting transmission of the content; and transmitting at least a portion of the segmented content to the external device responsive to receiving the second input signal.