About XAML
XAML stands for (Extensible Application Markup Language) which is Microsoft XML based language and it is best for designing good GUI. In old GUI framework WinForms is a GUI framework created in the same language which is used for interact with Graphical User Interface Environment for example C# or VB.NET but XAMLis another way like as HTML in which we are easily write and edit your GUI. it is an essential part of WPF. In development we are creates many Window form and Page which consist XAML document and project Code. The XAML file is play interface with all its elements and Code handles all the events and has access to manipulate with the XAML controls.
Related resources for XAML