What must occur for a permanent to be destroyed?

For a permanent to be destroyed, it must be dealt lethal damage or targeted by a destroy effect. Lethal damage is an amount of damage equal to or greater than the permanent's toughness, which results in the permanent being put into its owner's graveyard as a state-based action. Additionally, a destroy effect specifically instructs that a permanent be destroyed, meaning it will go to the graveyard unless it has some other effect that prevents it from being destroyed (for example, if it has indestructible).

The other scenarios don’t fulfill the requirement of destruction. Sacrificing a permanent is a distinct action that does not involve a destroy effect, and exiling a permanent is a different kind of action altogether that removes it from the game but does not equate to destruction. Similarly, returning a permanent to its owner's hand does not involve the destruction of that permanent. These aspects clarify the importance of understanding the distinction between different methods of handling permanents in the game.