Help and documentation are needed to supplement user interfaces because:
Any help or documentation that is provided should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.
Before tips can be provided on how to develop these features, one must first understand how operators use documentation. The fundamental truth is that most users simply do not read manuals. They prefer to spend their time on activities that make them feel productive. Therefore, users tend to start using systems before they have even read all of the instructions.
When users do want to read the manual, they are usually in some kind of panic and need immediate help. This indicates the need for good, task-oriented search and lookup tools for manuals and on-line documentation. Since many users rarely use the manual before they absolutely have to, it is not usually immediately available. This helps justify supplementing printed manuals with on-line help and documentation. Also, offering on-line help, with features such as hypertext and good search facilities, allows the users to access precise information quicker than with a paper manual.
On-line help has the advantage over documentation that it can be context-sensitive. For example, graphical user interfaces provide help with Tootips or "balloon help" when the user points to an element on the screen. One should remember that the user's problem often is related to wanting to do something else that is offered by the current system state, so it should also be possible for the user to ask task-oriented questions.
An important aspect of help and documentation, whether on-line or hardcopy, is the quality of the writing. This ranges from the structure of the information to the readability of the text. In fact, a study of on-line help concluded that "the quality of help texts is far more important than the mechanisms by which those texts are accessed".
The main principle to remember about on-line help and documentation is that these facilities add an extra set of features to a system thus complicating the interface just by virtue of existing.