If your Beoplay H7 are added to the Bang & Olufsen app, you can find the 8-digit serial number under "Product information -> Product settings -> About." The Bang & Olufsen app is available for download from the App Store and Google Play Store.
Alternatively, the serial number can be found on the packaging of Beoplay H7 or by removing the left ear cushion by turning it counter-clockwise. The serial number is located on the edge of the earcup.
