Why do England football team wear white kit?

Answer 1

The first international match of an english national team (in any sport) is a Rugby match between England and Scotland dated 1871. England choose to wear white because it was the color of the sporting activities at the Rugby school. When in 1872 the national football team made its first match, they inherited the color.

Note that untill 1980's, England's kit was all white. Just in the 1980'a Admiral technical sponsor introduced a fancy design which added blue and red elements which could erroneously recall the colors of the U.K. Flag, but are an hommage to the colors of the badge of the Football Association.

Answer 2

White is the traditional colour for England, the alternative shirt is red as worn in the World Cup Final in 1966