Add product to cart when using coupon code

Hi all,

For our company we want to send customers a 30% OFF coupon code and send them a gift when they use the coupon code, so our warehouse knows they have used the coupon code.

For example:

Customer receives their coupon code via our newsletter. When they have added the items to their cart, they apply the 30% off coupon code. When the code has been applied a product/sku has to be added to their cart automatically.

Does anyone here knows how to do this? I have been looking all over the internet, but can’t really find an answer to my question.

​

Thanks in advance!