To help you understand what social engineering is, we are going to provide a simple definition; that is, the psychological manipulation of a person so that the person provides confidential information.
Taking this definition as a starting point, social engineering has become a security problem that is difficult for applications to control. That's because the point of failure is in the fact that the user is a human, capable of being analyzed and manipulated into handing over secret information or credentials that make it possible to access a system.