IMEI number is not QR-code!
You can find IMEI number on the package:
KidPhone2 и FixiTime3 - turn on the smart watch, press the power button to see the mobile network signal level and battery charge level on the display, then quickly press the power button three times. You will see IMEI number.
KidPhone 3G - install the SIM card with internet connection, turn on the smart watch, the smart watch should see the mobile network signal level.
Open main menu, scroll to the "Details" item:
In the "Detail" item you can see IMEI number