The electronic device detects a pointing input to an edge area in a viewable screen portion on one side of a display screen of a display module, provides an affordance for changing a size of the viewable screen portion based on one or a combination of two or more of a time when a pointing input is maintained in the edge area, a moving distance of the pointing input, and a moving speed of the pointing input, and changes an area of the viewable screen portion to a size determined by the pointing input through a variable driver.