iPad locked to owner

Return it if possible. The device will never be usable without the original owners Apple ID and Password. It is also possible that it is a stolen device and the seller is not the original owner. Apple products should never be purchased from an unknown seller. See this article for the many problems you can encounter.

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

Ask the seller to remove the lock or give you a refund, or ask the people running the marketplace for a refund. It's an anti-theft measure.

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