add calculated value to payment

I'm trying to add a delivery fee to the payment total based on a delivery vs pick-up choice field.

how do i do this?

Hi,

Thank you for contacting us.

I checked and cloned your form, and it seems that you have already added an option for delivery with a special pricing of $20. Since it's already on the list of products and set as a required option it will be automatically added on the total cost. 

Let us know if you need further assistance.