Iron Ingots are ingots obtained by smelting of Iron Ore or by finding them in Dungeon and Stronghold Chests. Iron Ingots are used to make Minecarts, Rails, Compasses, Armor, Buckets, and Tools.
Iron Ore can be primarily obtained by the smelting of Iron Ore found while mining. However, they can also be found in Temple, Dungeon and StrongholdChests. Rarely, Zombies will drop items made of Iron due to them wearing Iron Armour or holding an Iron Tool, or just the ingot itself.
Iron is one of the most useful Items in-game, as it creates tools that are capable of mining all Ores and anything but Obsidian. It also creates the middle-tier armor, with Diamond being the highest tier. This makes it perhaps one of the most-used materials in Minecraft.
Iron is the item with more crafting recipes.
Because it's a rare drop by zombies, Iron can be considered a semi-renewable resource in Minecraft.