Methods for supplying, ordering, and transacting items based on motion images are proposed. The methods are applicable to a server and include the following steps. A first video stream is received from a first electronic device, and at least one item is identified from the first video stream to generate a frame and a tag associated with each item. An editing operation on a first tag is received from the first electronic device to generate first tag data. The first tag and the first frame are combined into the first video stream to generate a composite video stream. The composite video stream is transmitted to a second electronic device. In response to an ordering operation detected on the first item from the second electronic device, first ordering data is generated according to the first tag data to add the first item into an order list of the second electronic device.