If you give someone a link to complete a new form in SharePoint (like a survey), they normally get returned to the default list view after they submit the response. However, you can redirect them to some other page by adding the ?source parameter to the end of the URL link.
For example, Sandra Mahan has a link below to send a person to the survey response form. But by adding the ?source parameter to the end of that link, she redirects them to the survey's graphical summary view instead of the default page:
What they see after submission without the ?source parameter:
Default view of survey responses
What they see after submission with the ?source parameter:
Graphical view of survey responses
If you have ever been taken to a "thank you" page after submitting a form online, this is the technique that they are using.