How do I resolve 'iPhone Locked to Owner' issue after updating iPhone 8 Plus?

You don't. There is no official Apple store in Pakistan. You purchased a stolen phone from a store that does shady business practices.

Take this up with the store you purchased this from. Apple cannot help you with stolen goods.

You will not be able to use the device unless you can get the original owner to remove it from their account. Apparently they still had their account logged into the device and also because of that, they can track the device, which is not ideal for you.

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

attaullah161 wrote:

How can i fixe this problem

You CAN'T fix the problem. You've most assuredly been scammed and as others have said and as I mentioned in the second post you made about this, the phone is utterly, completely, totally useless to you. Apple will NOT help you. We CANNOT help you. If you can't get your money back, you own a useless brick. Recycle the phone responsibly. And read the link posted above in the post from Mac Jim ID with the link about buying used phones.

• Did you purchase the device used?
• Where was it purchased?