See When we bring a test charge let us say (+q) to a certain point, we exert some force. Our exerted fotce has to be equal or greater yo the electric field in order to overcome it. Thus the forces being opposite and equal cancels the effects of each other and hence the direction is undertermined. Since it is a compulsion for vector to have both magnitude and direction, hence here there is no direction but magnitude and hence we call it a scalar quantity.

When we bring a test charge let us say (+q) to a certain point, we exert some force. Our exerted force has to be equal or greater to the force exerted by the electric field in order to overcome it. Thus the forces being opposite and equal cancel each other and hence the direction is undetermined. Since it is a compulsion for vector to have both magnitude and direction, hence here there is no direction but magnitude and hence we call it a scalar quantity.