When I try to create a new project there is a different type of choises.
Windows Forms App (.NET) and Windows Forms App (.NET Framework)
Is ".NET" like .NET Core?
.NET Framework templates use legacy project file format which lists every file and cannot be edited without unloading. As the name says, they are only compatible with .NET Framework. Visual Studio will allow you to choose .NET Framework version.
.NET templates use modern project file format which is much shorter and can be edited without unloading. Visual Studio will allow you to choose .NET/.NET Core version (they just removed Core suffix starting from version 5). Also this project format is compatible with .NET Framework, but you need to specify it in project file manually (you can also specify multiple .NET versions).
The modern project file format is preferred unless you need features of the old format. As far as I know, the only thing you lose when you use this format is ability to reference assemblies from GAC or its extensions.
.net frameworkprojects are big and ugly,.netare small and cute. You can create both and see difference opening both with notepad. You should always prefer.netprojects