To develop a .NET app a developer first of all needs to install .NET runtime (CLR) on his machine along with BCLs. These two (CLR+BCLs) together may form a framework i.e. .NET framework. For developers feasibility Microsoft designed a developer environment or a tool i.e. Microsoft Visual Studio that includes inbuilt .NET framework. Just the developer needs to install this tool on his machine and start developing his apps. But once the developer starts using Visual studio, i. he needs to choose a language (C#, VB, J#, Pascal or any other 16 officially supported languages) that utilize the BCLs ii. he needs to choose the type of application (console, Windows, Web etc.) he needs to develop and start working out..

      Now the client (who utilizes the app developed by the developer), needs to install the .NET framework (required version) within his machine first to run the respective .NET App and then he can start consuming the app.