We require the device’s ESN be provided when request return, and ESN is usually as same as IMEI. But how to find ESN or IMEI? The way to locate this can differ quite a bit from device to device. For devices that do not have cellular connections, A serial number is requested instead.
Here are some support page resources from various manufacturer websites to assist in locating the ESN or serial number if needed:
You can continue to submit return request after you locate ESN or IMEI here