The serial number can usually be found inside the mobile phone. Remove the back case, look underneath the battery, and the code should be printed on a sticker inside the phone. Another quick way to find the serial number is to dial *#06# on the phone.
The serial number, or International Mobile Equipment Identity (IMEI) code, is a 15-digit code that is unique to each mobile phone. It is advisable to make a note of this number, as it is needed to block the phone if the device is lost or stolen.
Dual-SIM mobile phones have two unique IMEI numbers.