How could I know the IP address of Black mail sender?

How we can known, incomming mail (sender)location .?

• In our mail box ,only incoming mail address is showing , so in which type ,or in which s/w , we know incoming mail location like( sender country, city,state, place or system information etc.) ex. when A person is send mail to B person. Person B only known its mail address all details is hidden like location of person A. In which type person B known sender location like (country name ,state name,place or computer system Ip address connect in which network)

• Answer:

  - trying to catch your spouse?