1. An image forming apparatus including an information processing apparatus for arranging at least one dot, which expresses information relating to image data, in the image data, the information processing apparatus comprising: processing circuitry configured to create an edge image of the image data; determine a position near an edge in the edge image to be a position of the at least one dot; arrange the at least one dot at the determined position in the image data so as to form an electronic watermark in the image data, and cause the image forming apparatus to output the image data and the electronic watermark including the arranged at least one dot, wherein the determining of the position of the at least one dot includes automatically determining the position near the edge, which is nearest to a center of an area, as the position of the at least one dot, in the area having a predetermined position in the image data as the center of the area, and wherein the arranging of the at least one dot includes automatically inverting a pixel, which is next to the at least one dot and which is along a direction connecting the center and the at least one dot, into a white pixel.