iPhone Locked to Owner

The owner will need to remove it from their Apple ID. See these instructions:

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

If the phone was purchased from someone else, it would be best to simply return the device until the problem is resolved. If you are unable to get a hold of the person, then the device will no longer be usable. Some background on the device would be necessary to give you specific instructions on the options available for you. For example if the device was purchased from Apple or Authorized Apple seller by you and the receipt can be provided to Apple, then they will most likely be able to remove the lock.

AhmedGD86 wrote:

How to activation (iPhone Locked to Owner) iPhone 7 plus.

Did you purchase a used iPhone? If you did, read this --> https://discussions.apple.com/docs/DOC-250001038