In today's informational age modernization follows us at every step. The internet and smartphones have become a constant part of life, and mobile data usage is constantly increasing as a result. In thesis we will examine one of the most advanced current ways of developing cross platform applications at the same time - Xamarin.Forms. This enables users to develop applications for Android, iOS and Windows Phone platforms, as an open-source environment Mono and programming language C# bring us native applications for each platform. In some cases all functionalities per platform can be supported, and Xamarin.Forms way of developing applications enables us significantly higher functionality in comparison with other developing environments. In the thesis we will present basic elements of Xamarin.Forms with several examples to follow.