The control theory has significant applications in engineering since it provides us with structured approaches to examine and design nonlinear systems that are functional and remain stable. It is based on the dynamical systems and examines the manner in which the control theory can be applied in various engineering fields. Such methods of control as feedback, state-space and optimal control are developed to ensure that systems continue to run smoothly in cases where there is an unknown or an issue. They rely on modeling the dynamics of the processes happening in the world as a mathematical dynamic system. The paper discusses the improvements in both linear and nonlinear control processes and their effectiveness by giving real-life engineering examples in robotics, aircraft, and process control. Reliability, stable analysis and designing controllers using the current computer programs are given much attention.