Why Did Gandalf Turn White?

Gandalf was carried to Caras Galadhon in Lothlórien, where he was healed, given a new staff, and clothed in white, and thus became Gandalf the White.

What does it mean when Gandalf turns white?

It was that resurrection that Gandalf transformed from Gandalf the Grey to Gandalf the White. The god Eru, a Valar and the supreme deity of Arda, sent him back to Middle-earth to continue his mission.

What is the difference between Gandalf the Grey and Gandalf the White?

All this, Gandalf did when known as Gandalf the Grey for his ashen robes. The chief of the Istari remained Saruman the White, who also headed the White Council. But Saruman fell to the temptations of pride and impatience, and became both faithless servant and doomed imitator of Sauron.