Here is a quick video tutorial on how to make a normal map directly into Blender.
You can find of course lots of dedicated software to do this job, however, most of that software is paid. While you can still go that route, why not give this method a try first, and judge the results by yourself.
Thanks to ionwe:
You can find of course lots of dedicated software to do this job, however, most of that software is paid. While you can still go that route, why not give this method a try first, and judge the results by yourself.
Thanks to ionwe: