Discount Codes for Multiple Shipping Address Orders
When shipping to multiple addresses, discount codes must be taken on the cart page prior to reaching checkout.
During regular single address orders, discount codes are entered in during checkout.
To enable discount codes for multiple shipping address orders, go to Giftship –> Ship to Multiple Addresses –> and scroll down to the Discount Codes section.
There you will see an option to Enable / Disable at any time.

This option must be enabled in order for discount codes to work with the multiple shipping address checkout process.
Can't find the answer in our documentation?
Contact Support Discount Codes for Multiple Shipping Address Orders
Tax Calculation for Multi-Address Checkouts in the United States
Conditionally Hide the Multiple Shipping Address Toggle Based on Your Carts Contents
Sending non-physical products to multiple recipients
Using Tax Overrides for Multiple Address Checkouts
Enable Order Notes for Shipping to Multiple Addresses
Making the Multiple Shipping Address Checkout Cart the Default