iPlum is a business mobile virtual number. iPlum number is attached to the iPlum app. You can logout from one device & login into another device & use same iPlum number. The number is not locked to a device.
iPlum can send and receive regular text messages and short codes. But some apps like WhatsApp or Google check the number attached to the physical device. You would need to give them your physical device number to activate. iPlum may not work there.