In React, you can use event handlers to specify what should happen when an event, such as a button click or a form submission, occurs in a component.

To define an event handler in a React component, you can use the on[event] syntax, where event is the name of the event you want to handle. For example, to handle a button click event, you can use the onClick event handler.

Here is an example of how you might use an event handler in a React component:

import React from 'react';

function Button(props) {
    return (
        <button onClick={props.onClick}>
            {props.children}
        </button>
    );
}

function App() {
    const handleClick = () => {
        console.log('Button clicked!');
    };

    return (
        <div>
            <Button onClick={handleClick}>Click me!</Button>
        </div>
    );
}

export default App;

In this example, the App component defines a handleClick function that logs a message to the console when called. It then passes the handleClick function to the Button component as the onClick prop. When the button is clicked, the handleClick function is called, and the message is logged to the console.

Event handlers can be passed as props to child components, allowing you to manage events at a higher level in your application. You can also use the bind method to bind an event handler to a specific value, or use an arrow function to pass additional arguments to the event handler.