This high-level design document provides an overview of the tax payer registration system. It includes sections on system design, application design with process and information flows, data design with the data model and access mechanisms, interfaces, non-functional requirements around security and performance, and references. The application design section describes the registration workflow and includes a sequence diagram showing the information flow. The data design section shows the entity-relationship diagram for the main tables. Non-functional requirements specify security aspects like virus scanning and restricted file sizes.