Is this possible to get a VOA if I'm only staying 3 days and what paperwork do I need?

Hi, you cannot get VOA for that. If you will travel like Middle East-Shanghai-Middle East, you need to apply for a visa for that beforehand. But if you will travel like Middle East-Shanghai (less than 6 days)-HK/Macau or other places instead of Middle East-Middle East, you will be eligible for the free transit in Shanghai. No entry permit will be required then.