You can perform on-demand backups for a VM group or for a specific VM.
If virtual machines are encrypted using Azure Key Vault:
To perform backups, your Azure Key Vault and virtual machines must reside in the same Azure region and subscription.
You cannot run a backup for a Linux guest VM that has only the operating system disk encrypted (using Azure Key Vault). However, if this type of guest VM is included in a backup job, the job will not fail. The backup job will complete with errors (identifying the VM that is not backed up).
From the navigation pane, go to Protect > Virtualization.
The Virtual machines page appears.
To back up a specific VM, click the button in the Actions column for the VM, and then select Back up.
To back up all of the VMs in a VM group, on the VM groups tab, click the button in the Actions column for the VM group, and then select Back up.
To monitor the progress of a backup job, in the navigation pane, go to Jobs.