Here are some previous discussions that already cover this query, or matters very closely related:
- Creating an epilogue in the novel template: the short answer is that it is super easy to add an epilogue to the novel template, based on how we set things up. The long answer goes into exactly how we did that.
- Create a specific subtitle chapter for a few chapters: note this checklist presumes a lot of the background knowledge relayed in the discussion up to that point. While it concerns another matter (adding subtitles to chapter headings), you may find it interesting to read through, since the answer to your question should become self-evident once one knows how to do stuff like adding a subtitle to a chapter numbering line. It’s the same kind of solution, involving the same ingredients.
- Creating a preface. Some simple checklists that go over the basics of how to do this.
- Section headings when formatting for PDF. Another discussion going over some basic fundamental concepts of how to create different types of headings and assign them to the elements of your draft outline.