Destructive Margins:- Destructive margins are where two plates are moving towards each other. A destructive plate is where an oceanic plates meets a continental plate, the oceanic plate is forced down into the mantle and destroyed. This often creates volcano's and ocean trenches (very deep scetions of the ocean floor where the oceanic plate goes down).
Constructive Margins:- Constructive margins are where two plates are moving plates away from each other. Magma (molten rock) rises from the mantle to fill the gap and cools, creating new crust.
Conservative Margins are where two plates are moving sideways past each other, or are moving in the same direction but at different speeds. Crust isnt created or destroyed.