how to scan & save barcode on c#.net window form application

You can use the LEADTOOLS .NET barcode reading engine to read different types of barcodes (1D and 2D) and save the result (or barcode) to disk.
You can start by reading the following forums threads:
http://www.codeproject.com/Articles/690035/Choosing-the-Right-Barcode-for-your-Application

Here are some SDKs that have reading and writing barcodes features:

https://zxingnet.codeplex.com/

https://www.leadtools.com/sdk/barcode