How do you delete an Apple ID that you don’t know the people for?

You don’t. Only the person who knows the AppleID and the password can remove it. The original purchaser who purchased it from Apple or an Apple Authorized seller (and has a receipt to prove that) can get help from Apple. But Apple will not do anything for a second hand owner who encounters activation lock.

See -> How to remove Activation Lock - Apple Support

If your the original owner and have the information to prove that, start a service request here -> https://al-support.apple.com/#/additional-support