Setting up two addresses inside of FinishGreen is easy.
Why would you have two addresses per contact?
One is the Property in question.
The other is the Mailing Address in case it's different and the owner does not live in the residence you are interested in.

Out of the box, your contact card may only have "General Info."
General Info is used if you only have one address per contact.

If you want to include a second address such as the "Mailing Address", follow these steps.