A Prime Video PIN restricts the ability to purchase or watch content on an individual device.
Fire TV devices, Fire Tablets, and Fire Phones have their own Parental Control settings.
Note: Prime Video PINs only apply to the device they were set up for. Setting or changing your Prime Video PIN in the Prime Video app does not automatically enable or disable PIN on Purchase settings. PIN on Purchase can only be enabled or disabled through the Prime Video Account & Settings page.