Fortunately, Arcadier is able to provide this capability.
To do so, the merchants can proceed to Delivery Settings and click on 'Add Delivery Option'.
After filling up the necessary shipping information, click on the 'Price' button, fill in the delivery rate name, and for 'Range' field, click 'Onwards' and then put in the minimum purchase value the consumers have to buy in order to qualify for the free shipping. Afterwards, for the 'Delivery Cost' field, put '0' if you want to offer free shipping.