If you want to use the form in the contact page and you have already activated the WPForms plugin navigate to the plugin page>tools and go to the import tool.
Download the following item: wpforms-form-export-03-31-2019
And then extract it and get the json file included. Upload the file to the import tool. You are done.
There is a possibility that you have to go the contact page you have imported with the demo and paste the right WPForms shortcode. For example: [wpforms id=”923″ title=”false” description=”false”]