You can asynchronously create a new azure storage account using REST API in POSTMAN.
You can download files and folders from Azure File storage using this PowerShell script. You can use service principal who has access to Key vault and storage account. The storage account secret can be saved in Key vault to be accessed through PowerShell script.
REST API for the Blob service can be used to upload, manage, organize, and delete text and binary data.
Storage Account RestAPI PUT call can be used to create storage account using Postman