We investigate the vapor-liquid coexistence of polar and nonpolar fluids in the presence of a nonuniform electric field. We find that a large enough electric field can nucleate a gas bubble from the liquid phase or a liquid droplet from the vapor phase. Moreover, we show that gas bubbles can be nucleated far from the bounding surfaces. The surface tension of the vapor-liquid interface is determined within squared-gradient theory. We find that when the surface potential (charge) is controlled, the surface tension increases (decreases) significantly compared to the zero field interface. Finally, we investigate how the phase diagram in the temperature-composition plane is affected by nonuniform fields.