If I remember what the NPC said correctly, you get a tatoo by going in thaliak hall after writting a thesis for mastering whatever subject and/or progressing that field.

As lv.90 whatever job/class WoL would most likely qualify.
You don't have to be native of Sharlayan either since Thancred and Raha got one, but maybe be a citizen ?

as For DoL (and DoH) I can't remember if any gleaner has one, but if Thancred got one for being stealthy I can't see why not.