"Ok, I'm back w/ more info. I need to add a light fixture to a switch that currently controls 1 receptacle in the same room. Power goes to the switch and then to the receptacle which is an "end of run". There are no other receptacles/lights on this switch. I have full access to the wiring via the attic. Do I connect the light fixture wiring to the switch,the receptacle or should I do junction boxes in the attic. What is the "right" way of doing it? Pros/cons of different ways? "
People gave you several ways of doing it, all of which are acceptable, provided you do the work correctly. You can run the fan wiring to the outlet and connect it there. You can run it to the switch and connect it there. Both of those require snaking cables into walls. You can cut the cable in the attic, install a junction box (more likely two junction boxes because the existing cable won't be long enough) and run the cable to the fan from there, which likely is easier. Any of those will work and will leave you with a fan and outlet/outlets on the same switch, if that's what you want.
Personally, the easiest and best way is to forget about using the switch. Just find a hot line in the attic, use a junction box/boxes if needed (you might find an existing one, like one serving an attic light), and run a hot line direct to the fan. Then use a wireless remote to work the fan.