What you'll do: set up the small repeating text at the top of each printed page and choose where page numbers go. These are for the print PDF.
This is the Headers & footers section on the Design step. See Running heads & page numbers for the idea.

Steps
- Go to Design and open Headers & footers.
- Turn Headers & footers on.
- Choose a Layout — what shows on the left and right pages, for example Author / Title or Title / Chapter. A running head traditionally shows the book title on one side and the chapter on the other.
- Set Header position (toward the outer edges or centered) and where page numbers go (header, footer, or off).
- Fine-tune the font, size, letter-spacing and an optional separator or rule.
Tips
- Headers and page numbers are automatically suppressed on chapter-opening pages, where they'd look cluttered.
- These settings don't appear in the e-book — e-readers add their own progress indicator.