Another useful addition to a long document is the index. An index provides a list of important terms and other keywords from the document and gives a reference to the page number (or numbers) where the term appears. An index in a document is generated in a similar manner to creating a table of contents or a table of figures. To specify entries for the index, you mark the appropriate text items in the document.
The commands that you need to create your index are available in the Index group on the Ribbon’s References tab. The first step in creating the index is to mark the index entries throughout the document.