Add delivery options in the Content panel of the block ST100 ("Tilda Cart with Order form").
Open the Content menu → Input Fields → Add input field → select Delivery variants from the dropdown.
List the delivery options, separating them with a line break. If delivery is not free, add "=", then add the price (numbers only, the currency character is allowed).
Delivery option will be added to the cart. Delivery price will be added to the price of the product upon selection.