Since 2010s at business, digital transformation (DX) initiatives and digitalizing businesses have increased. The design of digital information systems is influenced by business and technological aspects and can have a considerable impact on the attractiveness of services. However, research on design science for DX or digitalizing business remains inadequate and not established. Meanwhile, the effectiveness of many methods established in the engineering field, including TRIZ that supports design and conceptual design, has been tested. The authors proposed “Creative and inventive Design Support System (CDSS)” in 2009 to support conceptual design in the engineering field based on TRIZ and suggested new methods “CDSSforDX” for applications in digital business and digital transformation (DX) in 2023. CDSSforDX is based on CDSS and has two additional processes, “strategic response” and “digital business strategy and DX strategy process,” as the strategy. In this paper, we present CDSSforDX methods and show the evaluation results and examples of using this methodology.