How to create a channel of communication with Connect-to-Call
This will allow recipients to call you with a click of a button while they are viewing your send-out.
You can activate this integration with Twilio in two ways. Either go to Settings -> Integrations -> Connect with Twilio or start sending out a document, go to the Engage Tab, and activate the Instant Phone Call from there.
When preparing your send-out and under the Engage Tab, you will notice an Instant Phone Call option.