Iron ingots can be primarily obtained by smelting iron ore in a furnace or blast furnace. However, they can also be found in temples, dungeons, and stronghold chests. Rarely, zombies and husks will drop items made of iron, due to them wearing iron armor or holding an iron tool, or just the iron ingot itself. Iron golems drop 3 to 5 iron ingots when they die.
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 (which can only be mined with a diamondpickaxe), ancient debris, and bedrock. It also creates the third strongest armor, with diamond armor being the second strongest, and netherite armor being the strongest. This makes it perhaps one of the most-used materials in Minecraft.
Iron is used in the most amount of crafting recipes which are about 29 total.
Iron is also incredibly versatile. It fills all 3 categories where it is efficient in building, attacking, and mining.
Because it's a rare drop by zombies and husks, iron ingots are considered a renewable resource.
Weaponsmith, armorer, and toolsmith villagers will buy iron ingots in exchange for emeralds.