To export multiple issues:

1. In Jira side menu, click Issues and filters → Search issues.
   
   
2. Filter issues to your requirements.
   
   
3. At the top right corner of the screen, click Export button (see the screenshot below).
   
   
   
4. The 'Export issues' dialog will open, now.
   
   
5. Choose the template (1) and output file format (2).
   
   
   
6. Click the Generate button.