If you were to press F1 on an object's Help Context ID property you would have seen this in help.
To create a custom Help file, you need the Windows Help Compiler and a rich-text format (RTF) text editor, such as Microsoft Word.
You can create a custom Help file to document forms, reports, or applications you create with Microsoft Access.
When you press the F1 key in Form view, Microsoft Access calls the Windows Help application, loads the custom Help file specified by the HelpFile property setting for the form or report, and displays the Help topic specified by the HelpContextID property setting.