What is the way to send Form objects in a service request?
You can send form object as a JSON in vFlow by creating C2S (which is nothing but a fancy name for request parameters) variable in API task.
For e.g. if you want to send a user form to Create_User_service, Create a Task of API type in TaskGroup and then in C2S1 add keyname user and in value input getVal("your_form_component_id")
and submit.
Thats all