Cross-Site Cloning: Connecting Different Jira Instances
You can setup connection between 2 Jira sites to facilitate project migration, Jira configurations clone, restored Jira issues
To connect two different sites, Command Center for Jira app’s should be installed in both the sites to make a connection and also region should be same both the sides.
Click on Settings in the left navbar - > click on Cross site connections card under connections settings

Click on ‘Add connection’
Enter connection name
Enter site URL

Click on ‘Generate connection token’.
Copy that token.
Open destination site & click on setting in left navbar - >Cross site connection card - > Click on ‘Activate connection’.
Paste connection token & click on ‘Activate’.