Software development is a set of process which includes identifying the user requirements, planning, programming, testing, and maintaining software.
In simpler terms, software development includes all that is involved between the conception of the desired application or software to the final manifestation of that application.
Software development is mainly of three types.
System software development is creating an actual platform with core functions for other software —for example, operating systems like Windows, Linux, iOS, Android.
Application software development is a program that is more specific to particular business tasks. Photo editing software, video players, Microsoft office are a few examples. With the emergence of PaaS (Platform as a Service) and SaaS (Software as a Service), web and mobile applications are the new trends. From watching movies on Netflix, shopping on amazon, or networking with LinkedIn.
Embedded software development is used to control machines other than computers. For example, industrial automation, telecommunication networks, and machines supporting IoT (Internet of Things).