Invitation letter related for L VISA

Hi, I am from India
I want to apply for L, I will be requesting a invitation letter from my Chinese friend, he is a student, he will fill out all info (Name, Add., contact number and his signature. Also, he will take car of my food, expenses and accommodation.
Kindly clear my below doubts:
1. My Chinese friend is a student, how will he get a official stamp ? is it mandatory, if yes than how?
2. Will I need to present bank statement with any criteria of money transaction?
3. Will my chinese friend will send a scan copy on mail OR what?

Thankful for your quick reply on this.