thats a normal map. you either bake them from a high poly to low poly with knald/xnormal/etc, or generate them from textures with tools like bitmap2material, crazybump, etc.
they are also often generated in tools like quixel suite/substance painter/3dcoat etc etc.
Xnormal Used the Most in Industries.
Still I use CrazyBump It is More Easy To Handle.
Thanks alot 