Ipad activation lock

If the original ID and password were yours you could attempt to retrieve and reset them respectively at https://iforgot.apple.com.

If the ID and password were set by a previous owner then only they can unlock it. Without the ID and password there is no way whatever that you can unlock it.

Above is correct. If not with the Apple ID and password, then the original purchase receipt showing the serial number, or similar legal purchasing or inheritance-related paperwork, and a discussion directly with Apple is the other option.