Weird West: Definitive Edition

Another easy one, just fire an arrow from your bow into a camp fire, brazier, oil lamp etc. to turn it into a "fire arrow" and the achievement should pop. A bow and arrows can be purchased from any of the tailors/gun shops - Grackle being the earliest. See my quick video for details:

Any arrows fired from your bow can interact with poison, electric or fire elements from hazards or items along the path of the shot. The simplest way to get this is to fire an arrow from behind a brazier, torch or other fire source to create a flaming arrow.