You can change what fields you have in the "Shipping Info Fields" area.  (Fields are what collect users info)

Click here to see a quick video related to this answer.

You can access this area here: YourDomain.com > Modules > Ecommerce: Products (mX) > Shipping Info Fields

By default these are the fields used.  The ones with the * are required fields.  There are some cases where the "country" field has been disabled, this will cause the option for international shipping addresses impossible.

If you are wanting to post a message to your customers on the page where they fill this information out.  Then you would go here:

YourDomain.com > Pages > Ecommerce: Products (mX) > Checkout: Customer Info (mX_customer_info.html) > Area A (Main) > Page Layout

see screenshot:

You can add a message to the top frame, or add a topmost frame.

Also if you add a custom Field in the Shipping Info Fields area, and you don't see it on this page.  You can choose to "Show" it here in the frame settings of the "Products:Add/Edit Customer Info Form".

(If the field isn't checked in the highlighted Column then it will not show on the page)

If you have questions about these options please feel free to Contact Support.