En Apple It may be that the iPhone to be purchased has a flawless external appearance, but that has been stolen , lost or simply the seller has forgotten to deactivate it, with the activation lock in place.
As you know, if this is the case it will be impossible for you to register with your own iCloud account and there is little you can do with the device. However, before you close your purchase you can check in presence or remotely, the protection status of your device and thus avoid later disappointment.
Apple has considered this scenario and created a tool to know the lock status of iOS devices, so that you can remotely know the protection status of the device. To do this, simply ask the vendor for the serial number or the IMEI of the device and access the Apple online service from any browser. Once there, enter either the serial number or the IMEI and the system will indicate your current status.
In the case of this the activation block is activated , you will have to require that it be deactivated (or better still, that it be deleted) before closing the purchase. How do I check this with the vendor first? iMore suggests accessing iCloud Settings on the iOS to purchase and there verify if Search my iPhone is activated. If it is, you will have to require the vendor to deactivate it, or something much more convenient for everyone, reminding them that must delete the device before selling it to you.