The structure of the SAD can differ from project to project as per stakeholder requirements and the nature of the project. Your project could be creating a new product from the ground, modernizing a legacy application, or moving the entire system to the cloud. For each project, the SAD document may differ, but, overall, it should consider various stakeholders' views and consider the necessary sections, as shown in the following screenshot:

In the preceding SAD structure, you can see different sections covering multiple aspects of solution architecture and design. The solution architect may choose to add additional subsections or remove some sections as per the project requirement. For example, you can add another introduction section to talk about the document's purpose, with a summary. For a transition project, you may add a subsection to present the existing architecture and compare it with the target architecture, and so on. Let's look into the details of each section.