iPhone is locked to owner

If you are talking about "activation lock" (an anti-theft measure), AND if you cannot remember the old Apple ID & Password (even using these instructions:--> If you forgot your Apple ID email address or phone number - Apple Support or these:--> If you forgot your Apple ID password - Apple Support ) neither we, just users like you, nor Apple can help you, sorry, unless you are the original owner and you still have the proof of purchase (receipt/invoice reporting your device’s IMEI or Serial Number). Should be this case, start your request using this link: https://al-support.apple.com/#/additional-support

Shouldn’t be this case, activation lock can be removed only by the previous owner, with the credentials that were used to activate that iPhone/iPad. Without those credentials, that device is useless to you.

You can also take a look at this support article:--> How to removeActivation Lock- Apple Support

Regards

Giulio

This phone is activation locked, and can only be unlocked by the original owner.

If you are the original owner of the iPhone, follow these steps to unlock it

Remove Activation Lock on the web if a device is offline

1. Go to www.iCloud.com/find.
2. Sign in with your Apple ID and password.
3. At the top, click All Devices.
4. Select the device that you want to remove from iCloud.
5. Click Remove from Account.

If you are not the original owner, you have to ask the person you've bought the iPhone from to remove activation lock..

See this article for reference https://discussions-kr-prz.apple.com/en/docs/DOC-250001038?commentId=250003637025

Only the person who originally set up the iPhone will be able to unlock the device. You will need to know their Apple ID and Password in order to proceed.

Do you have this information? If yes, do NOT provide that here. Keep it private and wait for more instructions.