Once the installation and configuration of the add-on is completed, you can add emails in Thunderbird directly to JIRA issue. 

To comment an issue, do the following:

1. Right-click the email you want to create a JIRA issue from.

   By default the body of the email is used as issue description. If you select a part of the email's body text, only the selected text is used as comment.

   At the end of the context menu, you can find the Thunderbird Integration menu items.
   

2. Select Add as JIRA comment from the email's context menu.
   The "Add a JIRA comment" wizard is displayed.
   
   

3. In the first dialog of the "Add a JIRA comment" wizard, you have to specify the issue you want to add the email as comment. To search for the issue, the dialog has five tabs for different search strategies:
   1. Full text:

   2. Issue key:

   3. Filter favorites:

   4. JQL:

   5. Recent Issues:

   In the "Other" tab of the "Thunderbird Integration for JIRA preferences" dialog, you can specify which tab is selected first by default.

   The search results are displayed in the "Search results" frame.

    

4. Select an entry in the "Search results" frame and click Next.
   The should be created in and the issue type:
   1. To specify the project, you can select a project from the "Select a project" pull-down menu or enter a project name in the "search for a project" textbox. While entering, matching projects are displayed.
   2. After specifying the project, the available issue types are displayed in the "Select an issue type" menu.
      Select the correct issue type from the menu.
   
   Click Next to continue.
   The second dialog of the "Create JIRA issue" wizard is displayed.
   
5. The second dialog of the "Create JIRA issue" wizard displays all fields that are available on the create dialog for the selected issue type in the selected project in JIRA.
   Mandatory fields are marked by an asterisk ("*").
   Enter the additional information and edit – if necessary – the displayed information.
   When done, click Next to create the issue.
   The third dialog of the "Create JIRA issue" wizard is displayed.
   
6. In the third dialog of the "Create JIRA issue" wizard, you can do the following:
   • Click Open Issue to start your web browser and display the created issue in JIRA.
   • Click Answer Mail to reply on the selected email.
     Defaults for the email subject and body can be defined in the "Reply" tab of the "Thunderbird Integration for JIRA preferences" dialog.
   • Click Open Issue and answer Mail to start your web browser (and display the created issue in JIRA) and reply on the selected email.
   • Click Mail settings to display the "Reply" tab of the "Thunderbird Integration for JIRA preferences" dialog.
   • Click Finish to finish the "Create JIRA issue" wizard.