how to use multiple folder into app.UseStaticFiles in .net core?

You can register UseStaticFolder twice:

app.UseStaticFiles(new StaticFileOptions()
{
    FileProvider = new PhysicalFileProvider(FolderToListen),
});

app.UseStaticFiles(new StaticFileOptions()
{
    FileProvider = new PhysicalFileProvider(FolderToListen2),
});