Availability Sets
Availability Sets is for virtual machine only. When you configure virtual machine with availability sets, it will make a copy of your virtual machine in isolated separate physical server, compute rack, storage units and network switches within a single datacentre within an Azure Region.
Availability Zones
Availability Zones can be use by many Azure Services including virtual machine. With Availably Zones, your workload will be spread out across the different zones that make up an Azure region. An Azure region is made up of multiple datacentres and each zone is made up of one or more datacentres. Each datacentre is equipped with independent power, cooling and networking.
Availability Zone has better SLA compare to Availability Sets
