The owner left I cannot enter Apple ID

if you mean activation lock?

activation lock is not a thing on the ipad it's a theft protection on apples servers

it needs to be removed How to remove Activation Lock - Apple Support

if you don't know your appleID password If you have forgotten your Apple ID password – Apple Support (UK)

then you will need the assistance of apple Activation Lock - Support (apple.com)

and or

Apple Support

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Contact - Official Apple Support

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Genius Bar Reservation and Apple Support Options - Apple

Presumably you are being prompted for your AppleID credentials - so as to satisfy the Activation Lock. You will require the AppleID an associated password that was last used to successfully activate the device - which, for the bona-fide owner, should be straightforward.

Here are the Apple support pages that outline the Activation Lock - and the only mechanisms by which it can be satisfied:

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Turn off Activation Lock – Apple Support

As you will discover, unless you are the owner of the AppleID that was last used to activate the device, you’ll not be able to defeat or bypass the Activation Lock. With documentary evidence that you are the original owner (such as sales receipt showing the serial number), Apple may be prepared to assist - otherwise they and nobody here will be able to help you.