Apologies in delayed response on this.
As mentioned on the Tableau documentation, the recommended Azure VM SKU's are D & DS Series VM with premium storage.
You can deploy the recommended Azure VM in your subscription (ref: https://learn.microsoft.com/en-us/azure/virtual-machines/windows/quick-create-portal) and can install the Tableau Server as documented in the Tableau Help documentation.
Here is another reference document that has the details of Tableau Server on Microsoft Azure deployment options.
Based on your subscription type, the region and the VM SKU the billing is determined.
In Azure, your subscription is billed based on the usage of resources on hourly basis.
Please check this pricing calculator to get the cost you will be incurring on your VM (depends on the hours the VM is running).
There is best practices documented here on how to keep the cost down.
Any actions within the VM (like the application installations) are responsibility on your end. Its shared responsibility depending on the actions. In this case Azure will not have the visibility of the application hosted inside the VM.
Ref: Shared responsibility in the cloud
Hope that helps.
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