I want to add a wall outlet by utilizing existing wires that are currently connected to my bathroom fan wall switch. I do not want a switched outlet. I want the outlet to have constant power. The existing fan switch only has a black and white wire connection. There are no other wires inside the fan switch box.
It's not possible. If you add a device on those lines you'll close the circuit to your light/fan and have several devices in series. This reduces voltage and creates a potentially hazardous situation.