Power-Ups turn Trello boards into living applications through additional features and integrations. Boards belonging to free users can turn on one Power-Up at a time, boards belonging to Trello Gold members may have three Power-Ups turned on at a time, and Business Class boards can have unlimited Power-Ups.
Go here to check out all our available Power-Ups.
Enable Power-Ups by selecting “Power-Ups” from the board menu and then by clicking on 'Enable' / 'Disable' to activate or deactivate the Power-Ups you would like to use.
The Trello App for Slack is enabled on a per-team basis—for more information, read our article on the Trello App for Slack.