Welcome. My name is XXXXX XXXXX would be glad to assist.
Black is Hot power, white is neutral and ground is the bare copper wire.
If the switch box only has 3 wires as you specified and the switch has 2 brass screws and a green screw, the location of the white and black do not matter in this instance.
A single pole switch merely connects the 2 wires connected together and turns on the light
If the switch has 2 brass and a black screw along with the green screw, then it will have 3 wires to connect plus ground. In that situation, the black screw is common on a 3 way switch setup.
On a switch box with only the 3 wires in the box, the white was used to get power down from the light, the black is usually the return to the light
That is a typical single pole light setup using only 2 wires/plus ground down to the switch
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