It's quite easy, they call esim
Instantly activate any cellular device and tablet or smart device that has eSim technology. Basica)ly anything made from 2019 and beyond.
ReUp also sends you the QR code that you will get scanned by the device being activated.
It truly takes 20 seconds and its great as primary phone line or secondary. No sim, no install. And all of it truly gets operated by the greatest GSM network in the USA