Your best option is to Google search "what is a PUK code". I am not an iPhone user so I don't understand that platform. There isn't much traffic here so not sure if someone will be on here to answer this. Maybe try Apple community or forum.
Visible no longer uses the PUK system. Visible has transitioned to not using that method. However Visible has a PUK code of 1111. This is for FCC regulations I believe. That is the heritage PUK number
