how do i know which sellers have epacket

[Olga]

Hi, I'm researching about the niche I want to work with before i start with alidropship.
But how odo know which sellers offer epacket. Yes i know you can see it once you are in the product but is there an eaiser way please.
China register mail, do you alos use it. I have as a customer and arrives quite fast

thanks