PIX Pay

Appreciate all the help with my last post about the Off White AF1 Brooklyns. I was gonna pay but it said I needed to do it through this PIX app or Payment thing. Does anyone know how that works? I know JMDY is a trusted seller so I wasn’t too concerned with that part, I just couldn’t figure it out. Might be user error and I’m just dumb but yeah. Any help would be great