React is a JavaScript library (not a framework) that creates user interfaces (UIs) in a predictable and efficient way using declarative code.
React works in declarative code.We use declarative code to create components, which is how we display information.
Essentially, components are reusable UIs which allow you to split the app into separate blocks that act independently of each other.
Components accept an arbitrary input with data (a prop) and return a React element to declare what should appear on screen.
They can interact with other components via props to create a complex UI.

State is the local state of the component which cannot be accessed and modified outside of the component.
It's equivalent to local variables in a function.
Props, on the other hand, make components reusable by giving components the ability to receive data from their parent component in the form of props.
State should contain data that a component's event handlers may change to trigger a UI update.
In real apps this data tends to be very small and JSON-serializable