I want to get unique ID for arduino mega which i am using. Can i know what is the method to get ID ,so that i want to send data to server with unique of the microcontroller.
Store it in EEPROM (I assume you mean "identity" and not "industrial design")
No Sir. I am looking for Industrial design ID.
The mega2560 does not have an on-chip unique ID. That feature is present on some microcontrollers, but not the mega2560.
Ok.
Would reading the Signature bytes give you the info you need?
You can get Unique IDs from other chips. Maybe just add a Winbond W25X40 (or similar). You';; get 4Mbits of storage and an Unique ID for a few cents. Also, many RTCs also come with unique serial number....
I really think it's something that every MCU should have - gotta love STM32s for these little things!
[a unique ID] is something that every MCU should have
It's gaining popularity. The Sam3x (Due) and SAMD (Zero, MKR1000) chips have a unique id included, as do all of the "Xmega" chips., and probably the new ATmega328PB (It's been moving around in the datasheet...) There's been speculation that similar data might be present in the older chips as well, but it's not documented. (there's mention of the "signature row address space", which has "holes" in it, and may extend beyond what is documented.)