
URL stands for Uniform Resource Locator, and is used to specify addresses on the World Wide Web. A URL is the fundamental network identification for any resource connected to the web (e.g., hypertext pages, images, and sound files).
example: www.google.com
Working:
Whenever user want to search user can enter the url in the web browser.The process of requesting the content in server is known as Request. Based on the user requirement the server will respond.The process of responding for the user request is Response.

Browser request the DNS(Domain Name Server) to convert the corresponding url to IP address.The domain name servers keep tables of machine names and their IP addresses, so when you type in Google.com it gets translated into a number, which identifies the computers that serve the Google Website to you.The browser then sends a request to that server for the page you want, using a standard called Hypertext Transfer Protocol or HTTP.
When server receives a request, it looks for the requested document and returns it to the Web browser. When a request is made, the server usually logs the client’s IP address, the document requested, and the date and time it was requested. Then each item is sent by the Web server to the Web browser and Web browser collects all this information and displays them in the form of Web page.