If your document has many headings, it's a good idea to add a table of contents in case it will be accessed outside Google Docs, for instance, if you export it as a PDF or EPUB document. You can even ...

You can make a table of contents in a Google Doc with a computer or iPhone, and create organized navigable sections for readers.

Learn how to add or insert Table of Contents in Google Docs without installing add-ons. Display index in Google Docs in two different styles.

If you're looking to better organize your Google Doc, you should consider adding a table of contents. Here's how to do it.