Board Thread:Support Requests - Getting Technical/@comment-27571552-20160428145949/@comment-856287-20160428185741

The table of contents is automatically added to pages with more than three headings on them; you won't see it any editor, Visual, or Source.

As Saftzie said, edit the page source and put the magic word  where you would like the table of contents to appear. If you would prefer the page have no table of contents on it at all, add  anywhere in the source.

See Help:Table of contents for more info.