The iron door is a block and you can use it as a barrier. You need to use a switch, lever, pressure plate, etc. to open up the iron door.
To make Iron Door, you just need Iron Ore and Iron Ingot using Furnace and then have to use the Crafting Table. Please follow the following steps to make Iron Door.
In order to make an iron door, the basic item that you need to find is iron ore. Equip your stone pickaxe and get at least six iron ore blocks. You will find some under the ground.
Iron Ingot using Furnace
Now you need to use the furnace to get iron ingots as you have required iron ores in stock. Go towards the furnace to add coal and iron ore blocks in it. Add six iron ore in the upper box and coal in the lower box to get six iron ingots in the right-side box of the furnace. Add these iron ingots into your “ready to use” stock.
Now you have to use the crafting table to craft an iron door. Open up 3*3 crafting grid and add six iron ingots in any two adjacent columns, as shown below. You will get an iron door in the right-side box to the crafting table. Add this door in your “ready to use” stock.