This is an accepted solution.
If you want to offer free shipping along with a discount, then you would need to set up a free shipping rate in Settings/Shipping. Our help centre document here goes into the steps needed to set up free shipping rates along with other information on how to set up your shipping area.
Our Product teams are actively looking into creating "stackable discounts" which would allow store owners to offer both a free shipping discount along with a product discount code. I do not have a timeframe for when or if this feature will become available, though it is on our radar.