The main goal of string theory is an attempt in order to address in-depth questions about fundamental physics. It is said to be a broad subject that holds a wide range of concepts. Concept of black hole, cosmology, nuclear physics, matter physics, etc., are some of those concepts in which string theory is applied in order to solve a variety of questions. In the field of pure mathematics, many developments are carried out successfully by the application of string theory. String theory is said to be a theory for everything, since it contains descriptive concepts of gravity and particle physics. It literally covers all fundamental forces and concept of matter physics, which makes it a self-contained mathematical structure.