iPad activation lock

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

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

https://support.apple.com/en-gb/HT201441

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.

Sorry - but you’re short of options

They can't; it's an anti-theft measure. Take it to the local police station, or if applicable, the Lost & Found department of the facility where it was found.

(181985)

There's no such thing as "finders keepers". What you're trying to do is called theft.

Doesn't matter how it was "found". It still belongs to the person who lost it. Turn it in to the local police.