here is the process of cbse 

Follow these steps to get the duplicate/triplicate copy of class 10th and 12th certificates.

1. Get a copy of FIR/ general diary report from the nearest police station (It is free of cost). You can also get an online FIR if your district or state police offer such facility.
   
2. Read the application form carefully. It contains details of your regional CBSE office and fees for providing duplicate/triplicate certificates.
3. Take printout of the application form and fill it out very carefully.
4. Visit your school to get
1. Signature (principal) and stamp (School) on the application form.
2. A letter from school on school letter head confirming that the said person has actually lost/destroyed the original certificate with principal signature and school stamp on it (Not required now).
3. If you don’t know your Roll number don’t worry your school has your record. Ask them they will provide it to you.