ipad

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

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, or unless you can secure the cooperation of the previous owner, you’ll not be able to defeat or bypass the Activation Lock. Without documentary evidence that you are the original owner (such as sales receipt showing the serial number), Apple won’t assist - and nobody here will be able to help you.

You don't.

Unless these people can remember their Apple ID info, and/ot still have the original sales receipt, for that iPad to take to a “local” Apple Store location, that iPad is a locked and useless device to you.

Failing all of this, just recycle this iPad responsibly.

There is nothing more to be done.

If you encountering the activation lock, there is nothing you can do except give it back - if they have their receipt, they can ask Apple for help.