Most humbly, my name is ____________ (name) and I am studying in _______ (class/semester) having ____________ (roll number).
I write this email to request you to give me the permission for late submission of the assignment due to _______________ (mention your issue – illness/exam/family issues/other). As you know that I have never failed to submit any project/assignment so, I promise you that I will submit the assignment next _________ (mention date – week/month/other) on __/__/____ (date).
I hope that you will consider this as a genuine request and support me. I shall be highly obliged to you.
___________ (Roll number)