When developing a Help system, the objective is to create one or more Help files. A Help file is the binary file that is actually displayed by the Windows Help application. In essence, the Help author’s work parallels the programmer’s development of an application. All the work and coding are produced for the express purpose of creating an application that a user can use. Similarly, all the writing and developing of Help files is done to produce a Help file that the user can view in Help.
That describes the purpose of a Help file, but what exactly is a Help file? In simple terms, it is a document. Like word-processing documents or spreadsheet documents, Help documents are defined in part by the information they contain. Spreadsheet documents are electronic ledger sheets that can perform calculations and other mathematical operations. Word-processing documents are electronic pages that can manipulate text and graphics. Help files are like word-processing documents in that they too can manipulate text and graphics. But Help documents also can include hypertext elements, such as links and hot spots, and multimedia elements, such as sound and video. And, unlike the other two kinds of documents, Help documents have no real-world equivalent. They exist only in electronic form on the computer. You can create a spreadsheet or a letter without a computer, but you can’t create a Help document without a computer.