A film/video editor is somebody who takes footage and will change it to make it more aesthetically pleasing. This is done by making cuts in the footage, or adjusting lighting, or adding music, etc.
Video editors can live anywhere they please, as long as there are movies being made around them to edit. It seems more common for them to live in bigger cities such as Los Angeles or New York.
A film editor usually lives somewhere fast paced, with a lot going. Somewhere with a higher population and more ideas for movie that could need editing. Los Angeles, New York, and Seattle are common places for film editors to live.