A card with a permanent effect is played from hand, just like any other card. The cards stays on the field after being played, its effect lasting continuously, and it does not go to the discard pile.
The player may decide to put an active permanent card into their discard pile. This stops the card effect immediately.
Each player can only have a single active permanent card at any time. Should they play a new one, the currently active one goes into their discard pile and the newly played card takes its place.