How do I define a deployment domain / hostname for use with a Webtask

[forumfred]

I want to allow my CC task to be triggered via HTTP and want to know how to define the app_deployment_hostname, in other words how do I define what the URL that is going to be used to trigger my task?

[tielman]

This is done from the Deployments Workspace by updating the deployment settings of the backend/deployment in question.

Like so:

Once updated and saved, remember to ​deploy the Domain change to the deployment in question by executing any deploy action on that deployment. (words)

Also please note this from our [docs] on the topic about domain names and what the full URL will look like (JourneyApps Documentation)