As a technical writer, you'll typically have to create indexes for the print books and for online helps you develop. The type of index we mean here is the classic back-of-book index that shows page numbers on which topics and subtopics occur within the book. An online index is much the same except that you supply hypertext links rather than page numbers.
McMurrey, David A. Illuminati Online (2004). Articles>Editing>Indexing>Technical Writing