Problem: You're collecting customer requests into Jira ServiceDesk project. When a SD agent is commenting on a request a customer should be notified via email.
Background: We assume that customer email is stored in a Jira custom field. Customer should only see agent's public comments and the comments may contain attachments (graphics, PDF etc). Those attachments should be sent to email as well.
1) Create a new notification of type Service Desk - public comment added as shown on the screenshot below. Add a JQL rule: project = YOUR_JSD_PROJECT_KEY to limit this notification only to the relevant project.
2) Provide Subject as shown above and choose the Jira custom field in TO section that stores your customer's email.
3) Using Template wizard generate a template by choosing:
- Details on first page
- HTML on the second page
- Fields Comment - Added, Comment attachment as shown on the screenshot below. For a better demonstration, we've also added standard field Assignee → Name and custom field SLA impact
Click "Next" and then "Copy & Close" on the last page of Template Wizard
4) Paste the generated code into your Notification template