White struck either side of the interval as the Lionesses, who had already qualified for the last 16, topped the pool with nine points, five ahead of second-placed Japan who will next face Canada or the Netherlands.
England coach Phil Neville made eight changes to the team who beat Argentina but it did not cause too much disruption as they dominated a Japan side lacking a cutting edge in attack.
White collected a superb through pass from Georgia Stanway before chipping the ball over Ayaka Yamashita to open the scoring in the 15th minute.
Yamashita kept her team’s hopes alive with a fine save to deny Toni Duggan’s volley from a Lucy Bronze cross on the hour.
Stanway and Rachel Daly marshalled the midfield well, although Japan looked potentially dangerous when England lost the ball.
Neville's side struggled as the game wore on but White sealed the win when she found the back of the net with a clinical finish after being set up by Karen Carney six minutes from time, her third goal of the tournament in two appearances.
England will play a third-placed team in Valenciennes on Sunday for a place in the quarter-finals while Japan will need to improve significantly if they are to reach the last eight.
Scotland were knocked out of the women's World Cup on Wednesday after Argentina came back from 3-0 down to snatch a 3-3 draw with a last gasp re-taken penalty following a dramatic intervention from the video assistant referee.
Scotland finished bottom of Group D with one point, a point behind Argentina who have a slim chance of qualifying as one of the best third-placed sides.
