On the group buy I just did I send quite a few packages to Canada and I was trying to do them as first class mail in bubble packages to save a ton (as opposed to the typical SFRB for rack etc). I had all kinds of problems doing it online and so I went to one post office and they said they don’t have the forms in store and that I had to do it online. So I went home and of course wasn’t able to do it again. I went to a different post office and they did have the paper forms so I shipped them from there, but I asked the guy how the hell to do this faster online and he said you have to create an online account as a business account. Only through a business account can you create the customs forms online for first class international mail. He said it doesn’t take any special work or paperwork, but you just needed to check the business account box. He said it was easy. I haven’t tried it yet. Take that for what it’s worth.
FYI it is the same in Canada. Anyone can get a business account with Canada Post. It gives you discounts on shipping.
Legit I named my company Moose