Add unique product attribute like serial number, IMEI

Hi guys,
I need to add unique product attributes like serial number or IMEI for each product to track which customer buy specific product. How to do this?
Thanks.

You can make use of SKU which is available for every product and will be distinct for distinctly identifying each product.

Thanks for reply
For example, we have 100 products with different IMEI, Is this means that we must add 100 product with IMEI in SKU and count = 1?

Make one product
Export it as a product spreadsheet
Copy the row 100 times (with hopefully auto incrment IMEI)
Import the product file

or a more smarter (long term) solution is to change the code (with a plugin) and automaticaly allocate the IMEI to an order when the product it is sold

Thank you for reply
Can you tell me more details about how to implement that plugin?

Clarify how/if you can "automatically allocate the IMEI".  If this is, for example,  on the product itself, then it may only be known at the time you fulfill the order.  And, it's not likely the IMEI is a sequential number, so the alternate is that you need to enter all the IMEI's into the system, and then if system "automatically allocates", you would need to be sure your shipping staff picks/ships the correct item.

As New York as noted there are some questions. Where does the IMEI come from ? What is it used for ?

If the IMEI is on the device then hopefully you can scan it in off a bar code at the time of shipping.

If it is not on the device/product there is one option we use. We have built a solution for eGift Vouchers. We buy the vouchers in bulk and the data comes in an excel file. We import that data into a table.
Then when a puchase is made for 1 to X products we allocate the number of eVoucher codes from the table and store it in the attributes when an order is made. The purchaser can then see the eVoucher code(s) in the email that is sent.

Changing the code / making a plugin is not simple and is a job for a developer or someone who wants to spend a lot of time learning the system