React, a versatile JavaScript library for building scalable applications across various platforms, utilizes components that receive inputs known as props to render UI elements. This guide explores setting default props in React, which serve as predefined values for props, ensuring components function even when certain props are not provided. It details the difference between default and optional props, highlighting that default props serve as fallback values while optional props do not hinder rendering if absent. The guide covers methods for setting default props in class components, functional components, and specialized components like react-select, using techniques such as ES6 object destructuring for functional components. It also explains how default props enhance component predictability and maintainability. The guide concludes by emphasizing the importance of default props in creating reusable React components and offers practical examples for implementing them across various component types.