Hub can be setup to send email notifications to users
Email notifications sent from Hub can be customized https://app.bigtincan.com/admin/email/templates
You can drag or click on the + symbol to add extra fields in the email subject
You can preview the template below the Email Body section further down the page
See https://taskexchange.zendesk.com/hc/en-us/articles/360001184595-Setting-Default-Values-for-Users on how to setup default notifications for users although the users have the control option to override the default notification settings applied to their profile.