Hi @Jaya Kumar
A very warm welcome to the Atlassian community.
This is Majid @ Exalate.
In order to fully synchronize your Jira instance to ServiceNow bidirectionally, you can utilize an an integration app such as Exalate. The app provides you fully customizable synchronization and of course, is a cloud based solution.
Please feel free to book a customized demo if you would like to see the product in action.