Frequently asked questions - Writer
From The Document Foundation Wiki
How do I get Roman numerals in the table of contents?
You have to set the numbering you want (here Roman numerals) in the page style. To do so:
- edit the page style using ▸ ;
- under the Page tab, in the Layout Settings area, set Format on the numbering type you want.
The table of contents will subsequently use this type of numbering update.