Posting Data to a Custom URL

To send form data and (/or) custom variables to certain URL, press your widget's button to open its settings 

and add a relevant action called 'Go to URL and send data': 

A position of the switch 'Use POST' / 'Use GET' defines if data will be sent via HTTP POST request or via URL GET parameters:

Using relevant controls you can add and specify any variable names and values. On the right, you may specify static (text) values manually or use the figure brackets icon to send dynamic values.