We are announcing encryption at host support as generally available for Premium SSD v2 and Ultra Disks. We already support encryption at host for other Azure Disk types, Premium SSD, Standard SSD and Standard HDD disks. When you enable encryption at host, that encryption starts on the Virtual Machine (VM) host itself, the Azure server that your VM is allocated to. The data on the VM host is encrypted at rest and flows encrypted to the Storage service.
To learn more, read the documentation. Please also note the regional availability of the feature for Premium SSD v2 and Ultra Disks here and other encryption at host restrictions here.