http – a webpage, website directory, or other file available over HTTP
ftp – a file or directory of files available to download from an FTP server
news – a discussion located within a specific newsgroup
telnet – a Unix-based computer system that supports remote client connections
gopher – a document or menu located on a gopher server
wais – a document or search results from a WAIS database
mailto – an email address (often used to redirect browsers to an email client)
file – a file located on a local storage device (though not technically a URL because it does not refer to an Internet-based location)
You can manually enter a URL by typing it in the address bar of your web browser. For example, you might enter a website URL printed on a business card to visit the company’s website. Most URLs, however appear automatically when you click on a link or open a bookmark. If the server name in the URL is not valid, your browser may display a “Server not found” error. If the path in the URL is incorrect, the server may respond with a 404 error.