I want the address field to prepopulate after a certain name is put in

That seems a little complex.

If you only want the user to enter their name and then their address will be automatically filled into the address fields, then you need to have like a database where these addresses are stored. Unfortunately, we do not have this with JotForm. However, if you have someone who can work on it or if you know PHP and JS, you can implement this in your form source code.

With JotForm, you can actually prepopulate fields base on the user's input. Let says a user input his name "john", you can create a condition that if name matches "john", insert "address1" on address field 1 and insert "address2" on address field 2 and so on. The problem here is that, everything should be defined on conditions. Meaning, the number of conditions is equal to the number of users you have. This is a bit laborious and troublesome if you have too many conditions.

However, if you want, you can use any of these widgets. This has the ability to pick up the address location automatically as long as the user accept the location permission that pop up on their browser.

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

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

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

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

Thanks!