You can mine Iron Veins from Mining level 0 and can start tracking them at level 25. Tracking automatically lets you see nodes appear on your compass (top) when nearby.
Iron ore can be used to forge Iron Ingots at the Smelter. Iron ingots can also be used to make low level iron apparel, iron weapons, iron tools, and Steel Ingots. You can also obtain this item at the smelter by downgrading Steel Ingots with Weak Solvent.