You can shorten a URL by using a URL shortener, an online tool to shorten the length of a long Web address. There are many online tools and services that allow you to shorten a URL, including Goo.gl, Tiny.url and Ad.fly.
Essentially, URL shortening is an online tool that allows you to shorten a Uniform Resource Locator, or URL for short. The technique behind URL shortening is by using an HTTP Redirect on a domain name that is shorter than the actual web page, which may contain a very long URL. The primary reason for URL shortening is because of convenience, especially with certain messaging technologies that limit the number of characters you are allotted.