Respected Sir/Madam,
With due respect, my name is ________ (name) and I am working as a _________ (designation) in _________ (department).
I am most respectfully writing this email in order to request you for sanctioning casual leave in my name for __________ (number of days) from __/__/_____ (date) till __/__/____ (date). Respected, the reason behind the same is ___________ (family function/ have to go somewhere/ exam preparation/ any other).
I shall be obliged for your kind support in this regard.
Thanking you,
Truly yours,
_________ (Name),
_________ (Employee ID)