While Trello doesn’t have great built-in printing support, it can print individual cards or entire boards.

To print all cards in a board:

  1. Click … Show Menu if Menu (right pane) isn’t already visible.
  2. Click … More (right pane), then Print and Export.

  1. Click Print… (right pane).

To print individual cards:

  1. Click card, then Share (pop-up).

  1. Click Print… (pop-up).

For more information, see: https://help.trello.com/article/812-printing-in-trello.