Create a Zapier Webhook

Search for Webhook in the list of apps. Note this requires a Premium/paid plan.

Create a new "Catch" webhook. Note the destination URL — you'll put that in the code fragment below.

Call Webhook from Prompt

Configure the Actions→Data Actions→Execute JavaScript (either Smart Link or Library)

//payload can be anythiing you want to send.
//store.customer.xxxx accesses all data fields uploaded and associated with
//the contact
var payload = {
   "email": store.customer.email
}

platform.buildCallExternalWebAPI("POST", "https://hooks.zapier.com/hooks/catch/########/XXXXXXX/").value(payload);