...
During the creation of a VM instance, when you add the default and optional additional NICs, you can determine if the IP addresses assigned to a NIC are static (persistent across restarts) or ephemeral (non-persistent across restarts). The process to add a static IP requires to reserve reserving the IP address. The public IP address may also have to be created first.
If you select choose to add a static private IP address to an interface, you will get the following window to reserve a static private IP address:
If you select choose to add a static public IP address to an interface, you will get the following window to create (if needed) and reserve an address:
...