Your message makes it appear as if you're running into Activation Lock and that this is a second-hand purchase. Removing Activation Lock requires either knowledge of the Apple ID and password or the original proof of purchase (POP) to remove.
Without the Apple ID and password, using the original POP requires contacting Apple Support so that the POP can be validated (matching serial number, IMEI, purchase date, and/or name on the receipt). A second-hand purchase receipt is not considered valid because the purchase date will not match Apple's recorded Date of Purchase. If the previous owner put the iPad in Lost Mode using Find My iPad, even with a valid POP there is no way for Apple to override Activation Lock.
My suggestion: contact the person you purchased the iPad from so that he/she can remove their Apple ID from the iPad.
Question: So I bought an iPad that already has and owner that I didn't know about. I would like to return it to them. When it goes to activation lock it says the owners left a message but it's in digits. Any clues