Which one is synchronous or asynchronous communication ? And Why?

I am confuse about both communication for the given scenario.I feel that every single list item can be synchronous communication.

• Order service calling the shipping service to proceed for shipment.

  • User buying items from User Interface(UI) Service resulting in invocation of Order Service.
  • User Interface(UI) service calling catalog service to get information about all of the items that it needs to render.