I t depends very much on what your knives are made of.
The “silver bullet” is something like theramark which will enable a visible mark on almost any metal.
http://www.thermark.com/content/view/64/140/
Other then that try something like these folks:
https://community.glowforge.com/search?q=engraving%20stainless
I was able to etch deeply into a high carbon steel ruler:
https://community.glowforge.com/t/etching-steel-yes/16265