In addition to the board/box, you will need to print enough pucks for each side. Unsurprisingly, for 12 Man Morris you need 12 white and 12 black. For 9 Man Morris you need 9 each. See the pattern?
The various Morris games (also known as Morabaraba) date back to 1400 B.C. 9 Man Morris features as one of several mini games in Assassin's Creed Black Flag.
For the rules of the various Morris games, please see: https://en.wikipedia.org/wiki/Three_men%27s_morris https://en.wikipedia.org/wiki/Nine_men%27s_morris https://www.thesprucecrafts.com/twelve-mens-morris-board-game-rules-412545