There are three ways to make delivery free across your store:
In the store item
For each store item, you can choose if you want to set delivery costs for the item. You can either set or remove this option by checking or unchecking the box called This item can be shipped in the additional options for your product in the Store Item Element.
In the payment options
In the menu of your Jimdo website, go to Store > Settings > Payment Options and select the payment option Local Pickup, so that customers will automatically not be charged for shipping. Instead, customers then pick up their orders from you for free.
In the shipping costs
For each shipping destination you can define that orders up to a certain amount have free delivery. To do this, in the menu, go to Store > Settings > Shipping Costs and check the box labeled Free Shipping for Large Orders, then enter the amount needed for free shipping.