The StarTrek.com website maintains an office listing for many main characters.
Enterprise-D
Jean-Luc Picard (Captain, USS Enterprise)
Office: Enterprise: Deck 1 Ready Room, adjoining Main Bridge
Geordi la Forge (Chief Engineer)
Office: Enterprise: adjacent to Warp Core, Deck 36 Main Engineering
Beverly Crusher (Chief Medical Office)
Office: Formerly, Enterprise-D: Deck 12/Room 1629
Guinan (Civilian Lounge Hostess)
Office: U.S.S. Enterprise: Adjacent to Ten-Forward lounge, Deck 10
Deanna Troi (Ship's Counselor)
Office: Formerly, Enterprise Deck 8.
Voyager
Kathyrn Janeway (Captain, USS Voyager)
Office: (2371-2378) Voyager, Deck 1 Ready Room adjoining Bridge
The Doctor (Chief Medical Officer)
Office: (through 2378) Adjoining Sickbay on Deck 5, U.S.S. Voyager
Chakotay (XO, Voyager) has an office aboard the Voyager. It appears to be on Deck 2.
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/80mQX.jpg)
Tuvok (Chief of Security, Voyager) has an office on Deck 6, proximate to the brig.
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/fsA3s.png)
B'Elanna Torres (Chief Engineer, Voyager) has an office that's directly adjacent to main engineering.
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/C0Tog.png)