Greetings Sari! Seems like a great example of a custom form and workflow. Just one question for you, how is the inspector determined? Is this a people picker field on the form that the initiator fills out? If so, then in the workflow task, you will assign the Approver to be the list item reference to inspector. The task you provide him can be a To Do task or request data task. Since you are not approving the form but asking them to fill it out or complete it, then you most likely will not use a Flexi Task or Request Approval task.

I'd create a workflow that would check the value of Inspector. If it is not blank, I'd send the email notification action for the Inspector to fill out his portion of the form.

Hi Andrew, Inspector is determined by initiator in people picker control. With the Request Data Task, I have understood that you have to add required filling-out controls to task form. Those controls are already in the list form and it's better to use same item for both filling-out sessions (initiator and inspector).  So is it then To Do task?

Correct. If you want the inspector to complete items on the same form you can use the To Do task. The purpose of the task is to notify the inspector that the initiator has created an item that needs their input. Provide a link to the item in the notification so they can easily get to it. Then the inspector will click complete in their to do task signifying they have completed their part.

Using a task provides some great features. Like reminders and escalation. If you simply use a Send Notification action instead, then you have no real means to track the inspector's interactions.