delivery method/amount after the order is created

[Miskab]

Hello, I would like to ask for a help with delivery method/amount after the order is created.
Is there somewhere possibility to remove delivery amount if the order was submitted by customer? For example if I decide to change amount of delivery or remove the amount totally from the order and give the delivery for free to customer. I cannot find it anywhere and then the Invoice cannot be added also.

Also when I want to give credit coupon to customer for delivery amount.. I am not able to. Only for whole product but not for delivery amount.

Can somebody help me with this issue? Many THANKS

[rocky]

You can't edit orders after they have been completed, except to refund products. It's a limitation of PrestaShop.

[Miskab]

Do you know if I would buy some additional module - if this would help?