Every phone Has A serial Number or an IMEI (International Mobile Equipment Identity).

The manufacturer of your phone did no just place it there for no reason, or just to fill an empty space, but it has a function.

Some phones are not worth loosing, that is why your IMEI is there to help you locate a missing cell phone or smart phone, or to block it from being used. So to actualise it, you need t know your IMEI first by dialing *#06# on your phone.

I will advise you to copy the IMEI and hide it somewhere for a rainy day. When you loose your phone, or it gets stollen, you can just call your service provider like, carl care, or the phone company and give them the IMEI so a they can use it to work on your phone.

Do inform your service provider if the phone is eventually found or recovred to hace it unlocked.