Customize the Cart page and check out option

Hello, I am working on a website where I need the cart page customized. I would like to add some service fee and only the service fee is payable the items fee is handled separately in a different manner only after order confirmation by a third party. The service fee is also dynamic based on the items being ordered. The payment mode is cash or Paytm or other means and not by credit card.
I also need some custom user input fields like Date to be added along with the items
what are the APIs available in the cart page to do these.

Hello.

Currently, customizing the cart and the checkout pages is not supported.

Feel free to post a Feature Request .

Regards!

Thanks Sam. I wont be able to use site without being able to add the service charge and other custom fields.

I would like to code the page.

Is there a way to code a repeater and connect it to the line items of GetCurrentCart ?