reset iPad without password

In addition to the above (correct) info, the previous owner can use iCloud to remotely release the Activation Lock, if they still have their Apple ID and password. That sequence is described in the following article, linked from what LotusPilot references:

What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support

If you don’t have the device passcode, that is easy to resolve:

https://support.apple.com/en-gb/HT204306

Your problem will be the Activation Lock as, if this is set, without the cooperation of the previous owner, you’ll not be able to reset this. Without documentary proof that you are the original owner, Apple will not assist. In this situation, there’s nothing that you r we can do to help.

https://support.apple.com/en-us/HT201365