The Send a Zap action sends a Zap with the subscribers information (Fig 1). 

Fig 1

To select which list to add the contact to, click the Send a Zap action node once you have added it to the Journey work area. Doing so will bring up the Properties pop-up on the right-hand side of the screen (Fig 2).  

Fig 2

Clicking the Webhook input field below the Send a Zap label will bring up a vertical menu of all your available webhooks from which you may choose the target list. Select the list by clicking its name.

Shown below are all current Actions. To learn more how different Actions work, click on the Action name below to read the associated article. 

• Send an Email
• Send a Notification Email
• Send a Text Message
• Send a Notification Text Message
• Perform Math on a Custom Field
• Add Contact to a List
• Remove Contact from a List
• Update a Contact Property
• Execute a Webhook 
• Terminate