In the checkout there will need to be a new box with a “find your closest shop” function. Like in the photo and video below. And the address the customers select it becomes the shipping address.
Moreover, in the Wordpress order background we need to see the ID code of that shop address. So we can find it in Excel when we export it. You should find this ID shop code in the API connect file.
I need you to work on this in a copied server, so our website doesn't risk to get messed up while you work