Activation iPhone Locked To Owner

Is the phone locked to your Apple ID? If so, remove the lock by supplying your credentials.

If the phone is Activation Locked to someone who voluntarily parted with it, then you need to contact them and ask them to help prepare the phone properly for transfer to you.

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

If you are unable to contact this person, or they do not want to help you, you have an Activation-Locked "brick" that will be of no use to you. Activation Lock is an anti-theft measure. We cannot remove it, and Apple will not remove it except in rather limited circumstances that do not seem to apply here.

See also:

The All Too Common SAD Reality of Buying a Used iPad/iPhone – Apple Community

You can't.

Activation lock is a security protocol that can't be bypassed. Only the person it is locked to can unlock it.

If you bought this from someone and it came locked, try to get your money back, you will never be able to use the phone.

If your phone is Activation Locked - How to remove Activation Lock -

How to remove Activation Lock - Apple Support

The All Too Common SAD Reality of Buying a used phone -

The All Too Common SAD Reality of Buying … - Apple Community