Zapier "webhook" to include Attachment FILE, not just the URL

I am using Zapier to send an email using a webhook. The email has an attachment (picture or PDF, can be either at time or both). when the email sends, it only grabs the URL for the attachment. i want the actual FILE. i know that if i use the UI inside of ZAP > OULOOK, i can call the FILE out and it inserts it properly… but i want this occur while using the webhook… anyone know the TAG i can use in the webhook pre-fill link to pull the FILE and not just the URL?