What are IMEI, MEID, and SN, and how to check them?

mei4dMobile devices are identified by unique codes known as MEID (Mobile Equipment Identifier) and IMEI (International Mobile Equipment Identity) numbers. While both serve asOn the following devices, find the serial number in Settings and the IMEIMEID (the MEID is the first 14 dits of the IMEI) on the back: iPhone 6. iPhone 6 Plus. iPhone SE