Azure API enables you to create Azure SQL Managed Instance using ARM templates. These are JSON objects that contain definition of resources that should be created. You can send these objects to the Azure REST API to automate creation of Azure SQL Managed Instance. In order to create a new Azure SQL Managed Instance, you... Read more

https://blogs.msdn.microsoft.com/sqlserverstorageengine/2018/05/15/creating-azure-sql-managed-instance-using-arm-templates/