When I ordered mine they arrived in a plain jiffy bag, inside the jiffy bag the seeds were in the usual supplier packaging.
It's stealth packaging if it's unopened.
It was my first time ordering seeds but I found it easy to order and they arrived pretty quickly.
there is more than one level of stealth i believe, if they can send the order in the original packs, they will.
i suppose something larger or bulky might need to be put in a more manageable packaging, in this case they will mark it for you