How to include help '?' in title bar of winform

The Help icon is only there when HelpButton = True and MaximizeBox and MimizeBox are both set to False. This is the windows standard. If you really want to go beyond and add a button anyway, you'll have to customize the titlebar.

This is not an easy task, it either involves many hooks, or a complete redesign of the title bar.

Are you sure you want to depart from the Windows standard? Wouldn't it be better to have Help available in the menu or on a toolbar somewhere?

In addition to the solution you must change FormBorderStyle to FixedDialog. To benefit help functionality use _HelpButtonClicked event in form.