Respected Sir/Madam,
My name is _______ (name) and I am working as _______ (designation) in your company for the last _______ (mention duration).
I write this email with the utmost respect and in order to inform you that I am unwell and I am going through _________ (cough/ cold/ fever/ headache/ body ache/ any other), due to which I request you to grant me the permission to work from home on __/__/_____ (date).
Due to this unexpected illness, I will not be able to work from the office and therefore expect that you will allow me to work from home for today. I shall be obliged for your kind support.
Regards,
__________ (Name),
__________ (Designation)