For more detailed information, visit this guide: Importing Test Cases.
1. In the desired project, click Tests.
2. Click the ellipses (…), and select Import from File.
The Import From File screen appears.
3. Double-click a file type to import.
4. For the Setup step, upload the test file, and fill in your desired settings.
5. Click Next.
6. For the Field Mapping step, map the fields in the first column, which are from the upload, to Test Management for Jira.
7. For the Data Mapping step, map the target values of the imported fields.
8. Click Import.
When the import is complete, a log with of errors and basic statistics displays.