Disclosed is a portable electronic device including a housing including a first surface and a second surface facing a direction opposite to the first surface, a display including a touchscreen panel exposed through the first surface of the housing and having a substantially rectangular shape, wherein the display has a first side and a third side extending with a first length in a first direction, and a second side and a fourth side substantially perpendicular to the first direction and extending with a second length which is less than the first length, and wherein a ratio of the first length to the second length is x:9, in which the x is equal to or greater than 16, a wireless communication circuit, a processor, and a memory. The memory stores instructions that, when executed, cause the processor to display at least one first icon having a first size on a first region in contact with the second side or the fourth side of the display or adjacent to the second side or the fourth side while longitudinally extending, display at least one second icon having a second size on the first region, based at least partially on an event occurring inside the electronic device or an event received through the wireless communication circuit, receive a user input for selecting the at least one second icon through the first region of the display, and perform a function associated with the event, based on the received user input. Besides, various embodiments understood through the specification are possible.