On Windows, the best IDE to run C# programs is Visual Studio. On Linux, the best IDE can be considered as Monodevelop. It is an open source IDE that allows you to run C# on multiple platforms i.e. Windows, Linux and MacOS. Monodevelop is also known as Xamarin Studio. It has a C# compiler to run C# programs.
Monodevelop has the following features −
Supports Linux, Windows and macOS.
MonoDevelop supports multiple languages such as C#, F#, Visual Basic .NET, etc.
It comes with an integrated debugger for debugging Mono and native applications.
Code completion support for C#, code templates, code folding.
Fully customizable window layouts, user defined key bindings, external tools
You can also try Visual Code, which is an open source IDE from Microsoft and runs on any OS.