Heading Styles guarantee that you will get automatic bookmarks that link to the sections inside the document. Once Heading Styles and a table of contents has been set on the documents, you need to make sure to check the following options to retain this information on the exported PDF:

 

  1. While on Word, click on File and Save As…
  2. Select Word Document to let the drop-down show and then select PDF
  3. Click on More Options…
  4. Click on Options…
  5. Make sure you check/enable Create Bookmarks using: and then either Headings or Word Bookmarks, most likely the first one if the document is properly formatted
  6. Then go ahead and click on OK and just proceed to save the file in the location of your choice.
  7. Verify on the exported document that the bookmarks link properly to the sections that they're meant to. The table of contents, if automatically created matching the Heading styles, it will also link to their proper sections inside the document.