If you're referring to the new bounty board in the medical area, the target NPC for each daily task is a random one.
Each task gives a hint at where the NPC is located.
- If location indicates "unknown," then they are in The Underground fighting arena.
- If location indicates they are resting, then - as andreihansa said - you can force an interaction with that NPC by meeting them via the menu at: Me -> Encounters -> Characters.
- To force this interaction, you might have to return to the Cellblock area, first (i.e. if target is an inmate).
- Otherwise, if they are wandering an area, it will indicate the area they are located and you must seek them out, there.
In the case of the "special bounty" NPC who is carrying contraband: once you interact with them, Attack them. If they surrender, or you defeat them, a Strange Pill should be looted.
(If they surrender, you might have to click "Punish" first to choose the Strange Pill).
I hope this helps!