Help: Context-Sensitive Help Overview
MFC makes it relatively easy to supply context-sensitive Windows help for your dialog boxes and commands. The MFC framework includes a help architecture that responds to the F1 and SHIFT+F1 key combinations and runs WinHelp.exe. With additional work, you can implement help for individual controls in a dialog box.
MFC supplies tools to simplify building your help files and several rich-text format (.rtf) files that document standard commands. You can customize these files to complete your help.