Fire is a harmful block added by vanilla Minecraft. Touching the fire will result in Player igniting.Ignition deals 1 damage per second.Mobs are also damaged by fire.Fire will spread onto burnable blocks around it and destroy them,and it will also destroy dropped items that come into contact with it.
Using a Flint and Steel on a burnable block will spawn the fire.Fire will also be spawned by a Bed exploding in Nether,Ghast fireball explosion or Blaze fireballs hitting the ground.A lightning hitting the ground will also spawn Fire.Crafting Fire can only be done by using the Uncrafting Table on chain armor. It will cost levels to do this however.
It is only used in crafting the chain armor from vanilla Minecraft. Which then could be turned into steel from a Smeltery.