I would like to offer Free shipping at the cart and checkout when a specific code is entered.
The way in which you can achieve this is by creating a Free shipping code under the tab
Promotions>Shopping Cart Price Rules inside this option you will be able to create the free shipping coupon. Here are a couple of screenshots to show how the coupon code configuration should look to achieve free shipping:
Once these processes have been completed you will need to set a delivery method to show as the free option at the cart and checkout processes. If this option is not set then the free shipping will not show at the cart or checkout process.
The following screenshot shows how to achieve this in Premium Matrix, but this is the same configuration for all WebShopApps extensions:
If you are having issues getting free shipping promotions to work see our troubleshooting guide for assistance.