If you are using the standard SO Form or one that was modified from it, it will show your sold to and ship to addresses. The bill to address is there in the XML and you can certainly add it to the form.
As for the Bill To drop down to change from the "same as sold to", you have to have an alternate Bill to address set up and/or National account to have additional options in the drop down list.
As for the Bill To drop down to change from the "same as sold to", you have to have an alternate Bill to address set up and/or National account to have additional options in the drop down list.