Scrum is a framework for developing and sustaining complex products that are based on the Agile software development process. It is more than a process; it's a framework with certain roles, tasks, and teams. Scrum was written by Ken Schwaber and Jeff Sutherland; together, they created The Scrum Guide.
In a Scrum framework, the development team decides on how to develop a feature. This is because the team knows best about the problem they are presented with. I assume most of the readers are happy after reading this.
Scrum relies on a self-organizing and cross-functional team. The Scrum team is self-organizing; hence, there is no overall team leader who decides which person will do which task, or how a problem will be solved.