Each item in Minecraft has a unique ID assigned to it, known as an item ID, this can be used in commands to spawn the item into the game. The item ID for mossy cobblestone stairs in Minecraft is shown below:
The Mossy Cobblestone Stairs item can be spawned in Minecraft with the below command. Cheats must be enabled before this will work.
|Max Stack Size||64|
|4x Mossy Cobblestone Stairs|