Before delivering the device for service, check the following:

The "Find My" feature must be disabled before we can perform service. It can be turned off on a working device from iCloud settings with your Apple ID password. If the device is not working or does not have internet access, the feature can be removed at https://www.icloud.com.
More information: https://support.apple.com/fi-fi/guide/icloud/mmfc0eeddd/icloud  

In the service of iOS devices, all data will be erased from the device. Therefore, a backup must be made either to iCloud or to your own computer using iTunes by the user. If you want a paid backup service, select the data backup service below. More information: https://support.apple.com/fi-fi/HT203977

It is always the customer's responsibility to back up data. Make a backup of the device data before sending it for service. If your device contains confidential or sensitive data, we recommend that you make a backup and erase it before sending it for service. The device's (Mac) administrator password is also required if data transfer or backup is to be performed (send it with the device). If you want a paid backup service during the service, make the required selection below. Data backup is only possible from a functioning device. Note that the devices' mass storage (SSD) is integrated into the main circuit board and cannot be removed. If the main circuit board is damaged, data cannot be backed up or recovered.

If the device is linked to a company's device management register (MDM), it must be removed from the service before sending for service. More information: From your company's IT support and from Apple https://support.apple.com/fi-fi/102300