I cannot find the artifact that henley requires at cambridge police station. Can anyone help me

Do you mean Scribe Haylen? That's an infinitely repeatable radiant quest that's in a different location every time. If the quest is active your compass pip should lead you directly to it. Make sure that this quest is active, and that it's your only active quest. What location did she send you to?

Yes scribe haylen, the quest is active and it just shows the police station. When I talk to her she keeps on asking for the artifact but doesn't tell me where it is and the quest only shows the police station. I am very frustrated

Did she ever tell you where to go to get it? Or did you just got there and have her ask you for the artifact without telling you where to go to get it? Are you sure you have the right quest active? It should be called Quartermastery.

Are you on PC or a console?

I am on PS4, thanks I do have the quartermastry but thought I got it from someone else. Will do that and see what happens

It sounds like you had the wrong quest active. Scribe Haylen is the one that assigns the Quartermastery quests. Be aware that it's an infinitely repeatable quest, so you only have to do it as many times as you feel like doing it. You won't reach an end point to them. She'll always have a new location and a new piece of technology for you to hunt down.