Q: forget

It requires the Apple ID and password of the previous owner. If you don't have it and cannot get it, then the device is useless to you. Return it for a refund if you can.

Find My iPhone Activation Lock

In the future check first before buying second hand: How to check for Activation Lock before buying a used iPhone.

Your Apple ID

    1. Forgot iCloud Password

    2.  Forgot Apple ID

    3.  Apple ID - Apple Support

    4.  Manage your Apple ID primary, rescue, alternate, and notification email addresses - Apple Support

    5.  If your Apple ID has been locked - Apple Support

    6.  About your Apple ID email addresses - Apple Support

Your iPad is just junk without being able to unlock it. You have an expensive paperweight. You might try going to a local Apple Store to see if they can help you. But there is a reason for this level of security.

You can take the ipad to an apple store.  You will need proof of ownership and a photo id.  Call the apple store before going.

R