Hi there,
Yes it is available to those who have registered the service .
One of the Prerequisites for the Multisession is that Azure AD-joined and enrolled in Microsoft Endpoint Manager by enabling enrol the VM with Intune in the Azure portal.
In short you can check all the Prerequisite for Multisession from here
https://learn.microsoft.com/en-us/mem/intune/fundamentals/azure-virtual-desktop-multi-session