Hello Sharma, Mukul,
Database backups are an essential part of any business continuity and disaster recovery strategy because they help protect your data from corruption or deletion. Azure SQL Managed Instance provides completely managed and automated SQL Server database engine backups. These backups enable database restore to a specific point in time within the configured retention period, up to 35 days. However, if your data protection rules require that your backups be available for an extended time (up to 10 years), you can configure long-term retention (LTR) policies per database.
Read for more details:
https://learn.microsoft.com/en-us/azure/azure-sql/managed-instance/automated-backups-overview?view=azuresql
If you delete a managed instance, all databases on that managed instance are also deleted and can't be recovered. You can't restore a deleted managed instance. But if you've configured long-term retention for a managed instance, LTR backups are not deleted. You can then use those backups to restore databases to a different managed instance in the same subscription, to a point in time when an LTR backup was taken. To learn more, review Restore long-term backup.
Hope this helps.
Thanks