Our Standard and Pro plans support print-ready PDF export and custom themes.
We have recently added the ability to customize margins when using a custom theme.
This is still very much an MVP: the margins apply to the print-ready PDF, and the inner and outer margins are averaged for the ebook theme. However, even though it’s currently pretty basic, it does the job: without this feature, our print-ready PDF exports are basically unusable at smaller print book sizes like those used in business books and in fiction: our default margins are 1 inch!
I don’t write fiction (except when talking about release dates, it seems), but after a fair bit of experimenting, the settings that my son just used for the print-ready PDF export of his novel are:
Font Size: 8.5 pt
Body font: IBM Plex Serif
Title font: IBM Plex Sans
Digest (5.5” x 8.0”, 14.0cm x 20.3cm)
Inner Margin: 1.25 inches
Outer Margin: 0.75 inches
Top Margin: 0.5 inches
Bottom Margin: 0.5 inches
This set of settings produced a print-ready PDF which looked good and which didn’t get rejected on Amazon when he used them (when coupled with their larger digest size book). We’ll see if it looks as good in the physical books once they arrive.
Anyway, to edit the margins of your book, go to Settings > Theme and scroll down about 1/3 of the way. There, you can customize the Page Size, Inner Margin, Outer Margin, Top Margin and Bottom Margin.
If you're thinking "they should have separate print-ready PDF themes and shareable theme templates", you're right! Someday we will!