Iron ore is relatively common, found at almost any Y-level, but more frequently below Y=64. Look for speckled grey blocks with orange-brown flecks. Mine it with a stone pickaxe or better. Smelt iron ore in a furnace to get iron ingots.
Minecraft
Finding Iron Ore
Find Iron Ore in Minecraft. Mine speckled grey blocks with orange-brown flecks using a stone pickaxe or better, then smelt for ingots.