Curl is a versatile command line tool and library used for transferring data with URLs, supporting numerous protocols like HTTP, HTTPS, FTP, and FTPS, making it essential for tasks such as file transfers, data retrieval, and API integration in web development. This tutorial explains how to use curl in PHP to make GET requests, a fundamental HTTP method for retrieving data from web servers. It covers initializing curl sessions, setting URLs and options, handling responses, and sending GET requests with parameters, demonstrating how to leverage curl's capabilities for controlled and efficient data exchange. The guide emphasizes the importance of understanding GET requests, which are read-only and idempotent, meaning they do not change the server's state, and highlights how configuring curl options allows developers to manage timeouts, redirects, and response handling for optimized interactions with web servers.