That is an anti-theft feature, the previous owner needs to remove their info.
Before you buy an iPhone, iPad, or iPod touch from someone other than Apple or an Apple Authorized Reseller, make sure that the device is erased and no longer linked to the previous owner’s account.
On a device with iOS or iPadOS 15 or later that is protected by Activation Lock, you see an "iPhone Locked to Owner" screen when you turn on or wake the device. Don't take ownership of any used iPhone, iPad, or iPod touch if it's protected by Activation Lock.
If you don't see that screen, follow these steps to check if the device is ready to use:
Activation Lock for iPhone and iPad
Find My includes Activation Lock — a feature that's designed to prevent anyone else from using your iPhone or iPad if it's ever lost or stolen. Activation Lock turns on automatically when you turn on Find My on your device.
support.apple.com
Check for Activation Lock before you buy a device from someone else
Before you buy an iPhone, iPad, or iPod touch from someone other than Apple or an Apple Authorized Reseller, make sure that the device is erased and no longer linked to the previous owner’s account.
On a device with iOS or iPadOS 15 or later that is protected by Activation Lock, you see an "iPhone Locked to Owner" screen when you turn on or wake the device. Don't take ownership of any used iPhone, iPad, or iPod touch if it's protected by Activation Lock.
If you don't see that screen, follow these steps to check if the device is ready to use:
- Turn on and unlock the device.
- If the passcode Lock Screen or the Home Screen appears, the device hasn't been erased. Ask the seller to follow the steps below to completely erase the device. Don't take ownership of any used iPhone, iPad, or iPod touch until it's been erased.
- Begin the device setup process.
- If you're asked for the previous owner’s Apple ID and password, the device is still linked to their account. Hand the device back to the seller and ask them to enter their password. If the previous owner isn't present, contact them as soon as possible and ask them to use a browser to remove the device from their account. Don't take ownership of any used iPhone, iPad, or iPod touch until it has been removed from the previous owner’s account.
What to do before you sell, give away, or trade in your iPhone or iPad
Use these steps to transfer information to your new device and, if applicable, remove your personal information from your old device.
support.apple.com
Before you sell/buy an iPhone
- If you paired an Apple Watch with your iPhone, unpair your Apple Watch.
- Back up your device.
- If you purchased an AppleCare plan for your device, cancel your AppleCare plan.
- Sign out of iCloud and the iTunes & App Store.
- If you're using iOS 10.3 or later, tap Settings > [your name]. Scroll down and tap Sign Out. Enter your Apple ID password and tap Turn Off.
- If you're using iOS 10.2 or earlier, tap Settings > iCloud > Sign Out. Tap Sign Out again, then tap Delete from My [device] and enter your Apple ID password. Then go to Settings > iTunes & App Store > Apple ID > Sign Out.
- If you're switching to a non-Apple phone, deregister iMessage.
- If in-store trade-in is available in your country or region and you're trading in at an Apple Store, stop here, do not erase your device, and visit your nearest Apple Store to pick up your new device. After a Specialist completes your trade-in, they'll work through the remaining steps with you in-store. If you're completing your trade-in online, continue to step 7.
- Go back to Settings and tap General > Transfer or Reset [device] > Erase All Content and Settings. If you turned on Find My [device], you might need to enter your Apple ID and password. If your device uses eSIM, choose the option to erase your device and the eSIM profile when asked.
- If asked for your device passcode or Restrictions passcode, enter it. Then tap Erase [device].
- Contact your carrier for help transferring service to a new owner. If you aren't using a SIM card with your device, you can contact them to get help transferring service to the new owner.
- Remove your old device from your list of trusted devices.