The following article lists what is required in order to be able to use the controls converter.
Visual Studio 2015 Update 2
.NET 4.6.1 - this is required if your Visual Studio does not have Update 2 installed. You can download it from here.
Solution that contains project with default .NET controls.
The WinForms converter crashes when converting a project with Visual Studio 2017 18.7 or newer. This is caused because in the latest version of Visual Studio a type used in the converter was moved. Additional information is available here: WinForms Converter crashes with Visual Studio 15.8 WinForms Converter is not available for VS 2019 yet because of breaking changes in Roslyn.