Contact Form Setup on Craft CMS
Without an entry with slug contact/thanks then the page just returns an error Variable "entry" does not exist. But still it doesn't draw any content from the entry. 


You do not need to create an entry for the Thanks page - in most cases it is easier to just add the actual text to your template file. If you do want to make it editable, then create a Single Entry, name it whatever you want, then go to Settings > Sections > yourSection and edit the uri and path variables. The URI should be contact/thanks, and the template path would likely be something like thanks.html