Crewman Jarvis was a female operations division crew member of USS Voyager while the ship was in the Delta Quadrant. She was in engineering following Voyager's transport there by the Caretaker. (VOY: "Caretaker" (per "Projections"))
She worked as transporter chief in transporter room 3 and beamed the two Vidiians Dereth and Motura aboard the ship. (VOY: "Phage")
She was on duty in engineering when B'Elanna Torres and Harry Kim searched for a way to free the microprobe from inside the micro-wormhole. (VOY: "Eye of the Needle")
She was working in engineering when a dead Vhnori body appeared in the Jefferies tube next to engineering. (VOY: "Emanations")
She was working in engineering when the Komar took over several crewmembers including B'Elanna Torres and when Torres ejected the warp core while under the influence of Chakotay. (VOY: "Cathexis")
A holographic duplicate of Jarvis
She was sitting at a table near the window in the mess hall and talking to a fellow officer when the former Maquis crewmembers Chell, Gerron, Henley, and Dalby talked about their training with Tuvok. She was also present when the four Maquis trainees later passed the section during their training with Tuvok. She remained in the mess hall and was present when Neelix talked to Tuvok about his flexibility. (VOY: "Learning Curve")
While The Doctor was delusional in 2371 he imagined that he and Reginald Barclay were going to disable the holographic memory core in engineering and that Janeway ordered holographic duplicates of Jarvis and Parsons to stop them. (VOY: "Projections")