How to make a shipping option free based on cart subtotal?

How to make a shipping option free based on cart subtotal?

First of all, it is necessary to check if the delivery method that you are going to rewrite is turned on at Magento Admin Panel → Stores → Configuration → Sales → Shipping Methods:




Then, create a new shipping rule at Magento Admin Panel → Sales → Shipping Rules → Add Rule. Select the required method from the Carriers and Methods dropdown and set the cart subtotal condition in Conditions tab:





In Rates tab, choose Replace action from the Calculation dropdown, make sure the Base Rate for the Order value equals 0, and save the rule:




With that, the original delivery charges are applied when the subtotal is less than $100:




When the required subtotal is reached, the delivery cost will be changed to 0: