You will need to know your Apple ID password to disable Find My.
3. Bring the proof of purchase of the device with you, in case it is needed for repair.
Don't forget to bring along - in addition to the device - any Apple peripherals that may be related to the problem you are experiencing.
Before sending your device for service:
If the iPhone you are sending us is paired with an Apple Watch, you will need to unpair the Apple Watch first. During the unpairing process, your Apple Watch will create a backup in iCloud. You will be able to use your Apple Watch again when your iPhone returns from our service.