WEbform get NID of parent node

I’m using drupal 7.58 with webform 7.x-3.27.
I have a car seller website. In the car details page (Content page) I have a form for customers that are interested in that car. The content type of the details page is “car”.
When the customer submit the form I would like the email to send details about the selected car. At the moment I’m not able to get any fields from the car info. In this case the parent content page tha is a car page.

Also I can see that when the form is submited, the NID registered in the database is NID of the form content and not the NID of the selected car content. So when I’m logged in and go to the selected car and press in Results page, it is empty because the NID registered in the database is the NID of the form block and not the NID of the selected car.

My question is, how can I make a content of type webform (I know I can put it as a block to use in the car page) and get the information of the selected car and send it by email? I just want to know how to get the car information and then use hidden fields in the form part.
I’d like to get information about the parent node as the form is like a child node in the car page.

Thanks for the help.

Bruno Morais

Drupal version: 

Source: https://www.drupal.org/taxonomy/term/22/feed