you need to contact the person that originally owned that device or if it is yours, go to your computer, download Itunes, and sign in with your account, verify yourself by using trusted device 6 digit passcode generator, then reset your device
Or if it is another persons device either contact them ,or you can get a service( mostly paid, but rarely free) that will crack it and the ipad is fixed
https://www.engadget.com/2014/02/11/how-to-fix-an-ipad-thats-been-disabled-after-entering-the-wrong/
https://support.apple.com/en-us/HT204306