“Why” questions are often the most important ones, and the business case is all about answering them. In an article for Project Smart, Simon Buehring addresses what he considers eight key sections of a business case. First, as suggested, is the “reason.” This explains why the project is necessary, but in the context of business strategy. Second, alternatives to this project should be explained and why they are inferior to the project at hand. Third, list all the benefits to be yielded from the project.
Follow that up by listing all the potential risks and the estimated cost, as well as the projected timeline. Then all that remains is investment appraisal and self-evaluation, where it is demonstrated once and for all that project benefits will compensate for and outweigh risks and costs. For further elaboration, you can view the full article here: https://www.projectsmart.co.uk/writing-an-unbeatable-business-case.php