erase all content and setting from an ipad without knowing an Apple ID password

If the iPad disabled or Activation Locked, unless you can independently obtain assistance from the owner of the AppleID that was last used with the iPad, the iPad is (and will remain) useless to you. If you are able to contact the owner of the AppleID that currently secures the device, they will require this information:

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

Here are the Apple support pages that outline the Activation Lock - and the only mechanisms by which it can be satisfied:

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Turn off Activation Lock – Apple Support

As you will discover, unless you are the owner of the AppleID that was last used to activate the device, you’ll not be able to defeat or bypass the Activation Lock. With documentary evidence that you are the original owner (such as the original sales receipt showing the serial number), Apple may be prepared to assist - otherwise they and nobody here will be able to help you.

Without the Apple ID, you cannot reset the iPad.

If you have proof of purchase, such as a receipt with the serial number, you can request Apple remove his Apple ID from it.

~Lyssa