1. Go to menu item: View
  2. Select [Navigation Pane] checkbox in Show tab

The following image shows you where to select Navigation Pane:

Insert Image

One of the simplest ways to structure a long document is to use headings styles to create logical divisions between paragraphs. There are default headings provided by Word 2013. You can find these headings in Home menu, and in the Styles section. If the document is well structured by using the headings, assistive technologies (e.g. Screen readers) will be able to navigate through the document easily. These default headings can also be used to auto-generate a table of contents. (If you plan to create a Word document with auto-generated content, remember that text marked with “Heading 1” will appear in the table of contents.)