how can unlock my device when it says iphone lock to the owner

You have to ask the previous owner who locked the phone to remove the phone from their account. If you don't know or can't reach them, then the phone is useless to you. The ONLY way Apple will ever help unlock an iPhone locked to owner is if you ARE the owner who originally purchased the phone and you have the original purchase receipt with the iPhone Serial Number clearly printed on the receipt. I'm going to assume you aren't the phones original buyer, so again, if you don't know who the owner was, you can't unlock the phone. In this case, you try to get your money back and if you can't, you recycle the phone responsibly and chalk this up to a bad buying decision.

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

You need to enter the Apple ID and Password of the person who set up the phone originally. If you bought the phone from another person, you need to contact them to get the information that you need.

How to remove Activation Lock - Apple Support

The phone is useless until the correct Apple ID and Password are applied.

This is called Activation Lock

Do you own this device? Is it your Apple ID signed into this device? Did you buy this from a person from the Facebook marketplace or something along those lines?

The owner of that Apple ID would need to go to icloud.com/find. They would sign in and select the device you now have and remove it. If that can't be done then you need to call Apple Support and provide proof of purchase to get the Apple ID removed - if it is not yours.

How to remove Activation Lock - Apple Support