If you need to gather custom information about each order when shipping to multiple addresses, you can enable notes for multiple shipping address orders. This option is found in the Giftship settings.
You can also change the label for the order notes to something more applicable for your store. This option is found on the same page under the "Language" tab:
If you don't already have an order note on your regular cart page, you can add it using the following code snippet. It is normally placed near the checkout button: