Each quote has a delivery address (where the job would be sent) and a postal address (where the quote is sent).
The delivery and postal address will be the default addresses setup for the chosen account (if they have been setup).
There are a couple of shortcuts available when editing addresses.
By clicking on the Lookup button to the right of the Building field for either address, a pop-up window will list any Delivery or Postal addresses for the account. Click on an address and it will be loaded.
If you modify either address and want to make the other address the same, you can click on the "Copy" button to copy across the changes. For example, if you modify the Postal Address and want the Delivery Address to be the same as the new Postal Address, click on the "Copy Postal Address" button above the Delivery Address and it will be copied across.
If you want to lookup a post code, click on the Lookup button next to the post code. If you've already entered a suburb and state, the post codes for that suburb will be shown in a pop-up window. You can also search for a post code in that window. Click on the relevant suburb and post code listed to load that into the address.