The Alarm.com account for the IQ Panel 2 is created using the IMEI number. This number can be found on the outside of the IQ Panel 2 box, on the back mounting plate of the panel, as well as in the About menu under 'Cellular'. It's also printed on the QR code next to the SIM card itself inside the panel.
The last 10 digits of the MEID is shown on Alarm.com as the Alarm.com Serial Number.