i have been assigned with a task to create an Add-In for auto desk applications. Please guide me where can i learn to create the add-in, because i am new to auto desk applications. Thanks in advance.
Your first port of call should definitely be the official Revit Developer Centre:
http://www.autodesk.com/developrevit
Work through the DevTV and My First Revit Plugin tutorials. That will provide all you need.
The Building Coder provides a comprehensive overview of the Revit API getting started material for self-learning:
http://thebuildingcoder.typepad.com/blog/about-the-author.html#2