Well if it is not too fancy use Markdown and then save supply:
- HTML/CSS Export
- Markdown Source
- PDF Export
MacDown.app is really useful for that.
If it is fancy you want to look at Serif Affinity Designer (and probably Publisher once it gets released) or Adobe InDesign (as long as Affinity Publisher is not ready)... and export to PDF.
I haven't used Markdown before. Sounds like something I should figure out. The rules are simple and don't need much formatting or any images.