There are 330,000,000 Gods and Goddesses in Hindu religion. Amongst all of the Gods, Lord Ganesh is respected and devoted as the first God to be praised. Ganesh is son of the Lord Shiva, the destroyer and God of all Gods. Ganesh is the elephant-headed God of good fortune and success, fond of all the finer things in life. Every God has their own day and people pray and worship them according to their days. Tuesday is Ganesh's day, a good day to start a journey. Represented with his multiple arms, each hand holding a different object, he is one of the most popular Hindu figures.
Ganesh's head was beheaded by the Lord of Death at birth but Parvati, his mother, wild with grief, called on the other Gods to supplant it with that of an elephant. It is believed that she ordered her followers to bring the head of whatever living thing that they find in their way. The first living thing they found was an elephant wandering around so they cut his head off and brought back to Parvati and then it was joined to Ganesh's beheaded body.
Well that is how Ganesh got the elephant head and whenever you see a God with elephant head, remember to pray for success and whenever you start any good thing do remember and worship him before you do anything.