My iphone locked by owner so how I unlocked my iphone

It sounds like the phone is Activation Locked.

Activation Lock is an anti-theft measure designed to make stolen and lost phones useless to thieves and to anyone they might sell phones to. We cannot remove it for you. Apple will not remove it – except in very narrow cases. I.e., you are the original purchaser, and have proof that is convincing to Apple.

How to remove Activation Lock - Apple Support

If this is a used phone, see

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

The phone can only be unlocked by entering the correct owner's ID and Password. If you are that owner, check this link...

If you forgot your iPhone passcode, use your Mac or PC to reset it - Apple Support

or this one...

If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support