When creating an app, you'll typically want to preview it on a number of devices. In order to set up those devices for testing your app, you'll first need a unique reference number from the device.
If you aren't already signed into your Apple iOS developer account, sign in using your authentication details.
Click Certificates, Identifiers & Profiles
On the next page, click on Devices.
Click on the plus button at the top right
Give your device a name for example “Johns iPad” and follow the below steps to grab the UDID from your device.
Plug your iDevice into a computer via USB and open iTunes where you can select the device from the top corner.
Hover your mouse over the Serial Number and left click once.
The UDID will be revealed which you can now enter into the UDID field of the Add Device screen.
Continue to add more devices as you need using the above method until you've added all devices that you wish to test your app on.
