While following the device registration process, the user has to enter the UDID number of the device.
To find the UDID of a device
- Connect the iPhone to a computer using USB, and then launch iTunes.
The page appears as shown in the following figure:
![Apple developer account enrollment UDID](https://docs.cedcommerce.com/wp-content/uploads/2017/04/UDID.jpg)
- In the upper-left corner, select the required iPhone.
- On the left navigation menu, click Summary.
- In the right panel, click the serial number of the device to display the UDID.
The page appears as shown in the following figure:
![Apple developer account enrollment Serial Number](https://docs.cedcommerce.com/wp-content/uploads/2017/04/Serial-Number.jpg)
- From the right panel, copy the UDID number to use it while device registration.