Jira Email This Issue offers custom field types to use screens (e.g. in workflow transition views) to specify parts of the emails being sent. To see the list of custom fields go to Issues --> FIELDS --> Custom fields. To set new custom fields click Add custom field.
Issue Attachment Selector Field
SINCE VERSION 184.108.40.206
This custom field type allows you to select existing attachments in an issue. The field can specify attachments to be attached to emails sent via event notifications, the transitions or when sending bulk emails.
1. Under Advanced field types, search for Issue Attachment Selector Field and click Next.
2. Give your field name and optionally a description and click Next.
3. Make sure to associate the field to the wanted screens. To edit that, click the three dots next to the name of a custom field and choose Screens.
4. Go to the issue you want to send in email. The field is present on the issue screen, and its attachments selected are rendered as links with inline editing supported.
Note: You can freely use this custom field type for your own purposes when you need to select attachments.
Use case - Specifying attachments during a workflow transition
Make sure to the attachment selector to the screen displayed by the transition you want to use for sending emails. Then on the Add Parameters To Function panel configure the post function to add attachments from the attachment selector field. Read more about workflow transitions here.
Use case - Attaching selected attachments in an event notification
Configure Email This Issue Event Notifications to add attachments to the email from the selector field under the Content panel in the Configure Notification Event page. Read more about event notifications here.