In Drupal 8, look for a plug-in called business rules to integrate
with webforms module
https://www.drupal.org/docs/8/modules/webform/webform-blog-posts-articles-%C2%A0presentations#webform-handlers
You could create a new node with every submission but you shouldn't in
the common case.
https://blog.mattarnster.co.uk/tutorials/create-a-webform-handler-in-drupal-8/
https://www.youtube.com/watch?v=3FAgt8aijYA