I can deprive a card so that others do not see it?

[Suany Maradiaga]

I don't want others to see other cards, can I make them private?

[Brittany Joiner]

@Suany Maradiaga welcome to the community! If you add the Amazing Fields Power-Up, you can create a custom field and set it so that only you can view it. You can also use the Private Notes Power-Up, which achieves something similar, but I've actually heard it's been a bit unreliable with performance lately. 

Lastly, you could just create a board that only you have access to for "private" cards that on you want to see, and then if you wanted other cards on that board from other boards, you could set up automation on those boards, or sync rules with Unito!

[Gaurav Kataria]

Suany, Trello does not allow permissions at the card-level. Anyone who has access to a board can view all cards on that board.