Unfortunately I've to say that you can't customize the notifications generated by JIRA Service Desk, but I'd recommend you to take a look into the following suggestion and set yourself as a watcher in order to receive new updates about that:
Hi Atlassian Community! This is Teresa from the Atlassian team. My colleague Paul Buffington @Buff and I are excited to share a brand new ITSM resource we’ve created – "The Complete Guide to At...
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