The .csproj file is one of the most critical files in any ASP.NET project. This file contains all of Visual Studio’s information to build your project.
As the name implies, the .csproj file describes how to build a project and contains information about the target .NET framework , packages, configuration and settings.
If you look inside your project, you will not find any file with a .csproj extension.
To edit the .csproj file, click on the project name inside Visual Studio, as shown below.
You will see the project file configuration (shown below). From here, you can edit the file and remove or add configuration.