Check if you have already logged in with your Apple ID by going to the iPad’s Settings and see the top left of the screen. If you are signed in, just make sure to have your password nearby.
If you don’t remember it, this link will support you in creating a new one.
If you don’t remember the email you used for this ID, this link will help you.
1- Click on Utilities folder
2- Select Settings or search for settings in spotlight
3- Sign in using your credentials
4- and add your credentials in the fields that have just popped up.
Kindly note that the Apple ID is linked to a free service that is not provided by SumUp. Apple is a separate company with which we are not affiliated, and therefore, we cannot provide any support concerning this matter (and therefore we do not have any access to or control over your Apple ID). An Apple ID is required to download any app from the App Store and is also needed to update your device to the latest version of the SumUp POS App.