Is it possible to allow someone to add items to a list?

In my form, I want to collect, for example, all cars that a person has. People have a different number of cars. Sometimes 1, sometimes more. For each car, I need certain information (i.e. model, year, year acquired, FMV and debt owed on car). 

Is this possible? How do I do this? 

Also, can I export answers to specific places in a Microsoft Word document or Excel spreadsheet? 

A configurable list widget will allow you to create a set of different types of fields:

http://widgets.jotform.com/widget/configurable_list

While filling out the form, users will be able to add more sets of fields as needed with the click of a button.

It is indeed possible to export your data to excel, as well as other formats:

http://www.jotform.com/help/44-How-to-Export-Form-Data-to-Excel