What if you have an existing document, and you haven't used Heading 1 etc. to format the items that you want to appear in your table of contents?

You have two choices.

1. You can go through your document and use Heading 1 etc. to format the items that you want to be listed in your table of contents. As noted before in this tutorial, you can customize the headings to any style you want by select Format - Style .
2. You can have Word create a table of contents by using Outline level styles. This is like creating invisible headings. For an overview of that process, see the next tutorial in this series.