...
Adding hashtag filters in Salesforce
In Salesforce, click Settings > Setup.
If you are using Salesforce Classic, click Setup located on the upper right pane.Search for "Package" and go to Installed Packages.
...
Look for "Jira Cloud for Salesforce" and click Configure.
...
On the Configuration screen, scroll down to the Comment Configuration section, and click the
Edit icon next to Comment Tag Filter.
...
Administrators can enter the hashtags they want to filter comments from Jira.
Info Tags must be preceded by a "#" and separated by a space. Also, please be aware that hashtags in Salesforce are case sensitive.
Viewing filtered comments in Salesforce
Filtered comments will appear in a Salesforce Case based on what hashtags were configured by the administrator (see above).
...
In Jira, to add a hashtag to a Jira Issue comment, simply edit the comment and add the hashtag anywhere in the comment:
...