At all the temperature evaporation takes place at the surface of the liquid.
When the vapor pressure is equal to the surrounding atmospheric pressure, it is called saturated vapor pressure.
When the liquid is boiling, the vaporization starts at the bottom of the beaker. But the bobbles will start forming only when the pressure inside the bubble is greater than the total pressure at that point in the liquid. When they are equal, the vapor pressure in side the bubble can be called as saturated steam pressure.