My requirement: I have a web app which collects leads. Whenever a need lead is created in my app, I push it to my Zap. From my Zap I was able to send an email to my Gmail account with lead info. 

To fetch the lead info I defined my output fields, which looks something like this.

{
 "name": "",
 "email": "",
 "mobile": ""
}

I was able to reference there fields in my email body. 

I have a new requirement, users in my webapp have their own clients. When I select an account, I need to show the list of Clients of that user and they will select one Client to move ahead. 

To achieve this I created a New Trigger to fetch the list of Clients linked to that user. Here is a screenshot of my Input Designer settings.

Here is the response when I call this Trigger.

j
 {"id": 123, "contact_name":"John"}, 
 {"id": 456, "contact_name":"Smith"}, 
 {"id": 789, "contact_name":"Roger"} 
]

I was successfully able to fire the trigger after my account linking step. 

In the final Zap, when I select my account, I’m successfully able to show the Client Names in a dropdown.

Here is a screenshot 

How do I pass the “id” in the next step? (Do This) when I send an email along with the Lead form fields?

Here is a screenshot of how I’m selecting the lead form fields in body of email.