This seems like a really dumb question, but it's just something I'm curious about

I have about 40 days until I get married, then I'll be sorting out my biometrics and shipping everything off to LA. I plan on using Global VIP because it seems a lot of people had good experiences with them (for the most part) and their rates seem pretty reasonable to me.
But there's a couple points I'm not entirely sure on:
1.) I'm under the impression when I send something to the courier, I'll have to use an airway bill, yeah? My fiance explained it to me, and I heard it mentioned once before here on the forums, but I wanted to double check to see if that was the right way to sort out all the payment issues in terms of shipping the package back and forth.
2.) All I need to do is print off the order form off the website and include the payment, I think? There isn't anything special I need to send with the actual application, just those two things?
3.) Do I need to let them know ahead of time that I'm sending a package down to them? I don't know if I need to call or email ahead of time, or if they know enough what to do with it with the order form included.
Again, I feel kinda dumb, and if these things are addressed somewhere else on the forums, my bad

I haven't really read anything about these things, and they're floating around in my brain trying to cause me more anxiety than I need right now.