shipping rate

I get shipping rate from third party..
the third party name is appear in checkout cart but rate still 0.00 (Zero).
What is the issue?

Thank you.

Make sure you don't have any "free shipping" enabled
  - Product  (if all products are 'free' shipping the cart is free shipping)
  - customer role gets free shipping
  - free over $X
  - discount (applied to shipping)

Thank you.
Where can I request shipping service after order complete?

Thank you.

RE:  "request shipping service after order complete"
I don't understand your question.
Shipping service/method selection happens during checkout; the customer selects the service.  Then the final page confirms the order.  If you are asking how to Edit the Shipping method as an admin, you can do that on the admin edit Order page.

I want to trigger pick up service after order complete, automaticly after client pay for his order successful and complete order from user interface.

Thank you.

Clarify "trigger pick up service "

Send request to third party to pick up packages.

Thank you.

Shipping Provider plugins in nopCommerce typically just get (show) methods/rates.  The store owner needs to arrange the actual shipment including scheduling pickup.  If you want shipment/pickup to be automated, then you may need to use a service/plugin like ShipStation.

Yes I want shipment/pickup to be automated, I develop plugin Like ShipStation, I get rate but I don't know how can I invoke pickup service automated after customer complete order.

I can see this action in ShipStation controller, Is it invoke after customer complete order?

        public IActionResult Webhook()
        {
          
        }

Thank you

ShipStation uses webhook because it's an external service.  In your case you probably just need to set up your shipment in the OrderPaid event handler.

public partial class EventConsumer :    IConsumer<OrderPaidEvent>
...
    public void HandleEvent(OrderPaidEvent orderPaidEvent)
...