What software engineering fundamentals apply to all types of software systems?

Software engineering fundamentals that apply universally include requirements analysis, which ensures that the software meets user needs; design principles, which guide the architecture and implementation of the system; testing methodologies, which validate the software's functionality and performance; and maintenance practices, which address updates and bug fixes. Additionally, version control and documentation are essential for collaboration and long-term sustainability. These principles help create robust, efficient, and maintainable software systems across various domains.