URL full form is uniform resource locator. A uniform resource locator, or URL, simply identifies a specific location on the World Wide Web. A distinct resource should be accessible via each valid URL. One example of such a resource is an online webpage, but it might also be a CSS file, an image, etc.
In practice, there are a few notable exceptions; the most common of them is a broken or outdated URL. Being that the Web server is responsible for both the URL and the resource it points to, it is the responsibility of the web server’s owner to maintain the integrity of both.
The scheme is the first segment of a URL, and it specifies the protocol that must be used by the client browser to retrieve the resource. For most websites, HTTP or HTTPS is the protocol of choice (its unsecured version). Either of these is needed to address a web page, but browsers can also process additional schemes, like mailto: (to launch a mail client), this way you shouldn’t be startled to see them.
Entering a URL in a browser’s address bar will take you to the associated resource. Nonetheless, this is just the beginning.