Xamarin is a company that builds tools for developers and has two specifically products Xamarin Platform, and Xamarin Test Cloud.
Once you have Setup and install your Xamarin environment, you will be satisfied with the advantages it gives you.
C# developers are able to write with the platform all their logic in one language and the majority of the code can be shared with a regular app. Such Xamarin forms can help a programmer to avoid different platform’s specifications and give a universal user interface language, which maps to the related platform’s controls depending on where this or that code is running. You have a great possibility to use the same core within many platforms.
Xamarin is better from other tools because its code is compiled into the native code of every platform, in other words, it is faster and can match the usual language.
Speaking about Test Cloud, it allows making the automated testing on nearly all devices. A developer creates test scripts that will check the application functionality and such test scripts are then run on a numerable amount of devices. Xamarin gives a developer the opportunity to use many devices for Windows, Android, and iOS. In the hole, there is less code for maintaining. By using Xamarin you are able to reach almost all devices for Mac, iOS, Windows and Android from the one codebase and deliver the efficient application.