Which object should be added to a process model to initiate a process after a user submits a form?

To initiate a process after a user submits a form, a Start Form is the appropriate object to include in the process model. The Start Form serves as the entry point for users, allowing them to provide the necessary data required to kick off the process. When the form is submitted, it triggers the initiation of the process flow, thus enabling the subsequent execution of tasks defined in the model.

A Task Node is used to represent individual tasks within the process, and would not serve the function of initiating the process. An End Event signifies the conclusion of a process, and therefore does not initiate anything. A User Input Task is specifically designed to allow for interaction during the process flow, but it occurs after the process has already started, rather than at the initiation point. Thus, the Start Form is essential for starting the process in response to user input.