Pyrography is burning designs into certain materials like wood, using some kind of heated instrument to create decorative burn marks. Today, this is done mostly by using specialized burning or pyrography tools.
Many of the wood burner sets come with stencils you can use to apply various designs. You can also simply go freehand and design your own image. The third option is to transfer your own image onto the wood surface.
Facing a black wood surface, even if it has a design on it, can seem a bit daunting. How do you burn in the design? Going on a workshop, looking at some YouTube tutorials, or purchasing a good book can help.