Provided are an image forming apparatus with a touchscreen and a method of editing input letters using the same. In the method, an inputted text is displayed on the touchscreen using keys of the soft keyboard. A letter to be edited is received from the displayed text. At least one of coordinates representing adjacent keys of the soft keyboard is determined based on a coordinate corresponding to a location of the received letter on the touchscreen. At least one of the magnified images of the adjacent keys corresponding to the determined coordinates and functions keys is displayed. The displayed text is edited using a letter corresponding to one key that is selected from the magnified image of the adjacent keys.