I have a huawei honor 4c model chm-u01 ... but clean its the rest of s/n phone. how can i find complete s/n?
Do you mean IMEI number? If yes then, There are a number of ways to get your IMEI number.
First, you can go to Settings – More – About device – Status. Scroll down and you should see IMEI listed on the screen.
Secondly, often the box that your device came in will have the IMEI printed on the label of the box or on the invoice.
Thirdly, if your device has a removable battery then open the cover and remove the battery. Your IMEI should be on a serial number plate and your IMEI number should be shown there.
View more details in Huawei Honor4C Manual.