The IMEI number also called International Mobile Station Equipment Identity usually unique, is used by 3GPP (i.e., GSM, UMTS and LTE) and iDEN mobile phones, as well as some satellite phones to identify valid devices.
It Could be displayed on-screen on most phones by entering *#06#.
The IMEI (14 digits plus a check digit: 15 decimal digits) includes information on the origin, model, and serial number of the device.The generator will gives you IMEI numbers for testing only. Here is an IMEI validator to validate the result.
If you want to generate other mobile info not only imei, here is an Android Device Information Generator.