The electrons flow from negative terminal of a battery to the positive terminal because as the charge of electron is negative, it will get repelled by the negative terminal of the battery
Conventional flow actually assumes that the current flows out of the positive terminal, through the circuit and into the negative terminal of the battery
It actually says that direction of flow of current is in opposite direction to the direction of flow of electrons
The direction of current will not change even a resistor is placed in the circuit and it generates a potential difference across the resistor
But the current tries to move in such a way in which there will be less resistance to the flow
