WebClient is a class in C# that provides a simple way to make HTTP requests to web servers. You can use it to download or upload data to a server, as well as to send HTTP requests with specific headers, methods, and parameters.

Here's an example of how to use WebClient to download a file from a web server: 

This code creates a WebClient object, sets the URL to the file to download, and sets the output path to save the file to. Then, it calls the DownloadFile method of the WebClient object to download the file from the URL and save it to the specified output path. 

example of how to use WebClient to send an HTTP GET request to a web server and retrieve the response: 

This code creates a WebClient object and sets the URL to the web page to retrieve. Then, it calls the DownloadString method of the WebClient object to send an HTTP GET request to the server and retrieve the HTML response as a string. Finally, it writes the HTML to the console.