The most common way comics are made (especially in the mainstream/superhero realm) is with the following people:
- Writer
- Artist (Pencils)
- Inker
- Colourist
- Letterer
I don't know the specifics of how work gets transferred around, but I doubt that many creative teams go so far as to live with each other. I know that, for example, Green Arrow has a Writer/Artist team that don't even reside in the same continent.
There can be some combination of the above jobs though, since a lot of Artist will ink their own work as well as penciling it. A few also colour their own work, such as Frazer Irving.
Creators who both write and draw are more common in the indie world but there are a lot more artists at DC/Marvel who are also trying their hand at writing, to various degrees of success.
The amount of control the writer has over the art varies depending on the writer. Some (like Alan Moore) will send detailed scripts with very specific instructions of what each panel should show, whilst others will send basic descriptions and allow the artist more free reign over what they draw.
What kind of stories/genres are you interested in?