You need to apply for a permit it's easy to get from the government website. I looked into it a bit but ran into problems with the info required to be provided by the shipper.
I don't know if a 3 Rd party option exists but I would go that route if you can.
If you are doing it illegally I'm not giving advice on that for a couple reasons.
1. I don't give advice on illegal activities
2. It's certainly not in good interest of this site