Hi Audrey,
Then depending on your need you can:
- Look at the back of the kit. On the sticker it is address after M. (1st Line)
- Call a function in your embedded code to get this address via SW:
- ATMO_MK64F_BLE_GetMacAddress if you are making use of the Rapid IoT Studio environment.

Using a docking station or latest OOB app from the studio you would see this in a terminal:
'Got MAC Address: 00:60:37:12:7A:A5"

NXP in this case starts with: 00:60:37 for This product.
Then 12:7A:A5 will be unique for each kit.
Comparing with the sticker at the back of the kit you can remove intermediate 4 0 bytes inserted