I am buying a software, but the distributor said that it needs the valid ip configured in the network interfaces, is it possible?
If your software vendor requires a public IP address to be bound to your VM instance, the answer is that this is not possible.
In Google (and AWS, Azure, etc), public IP addresses are not bound to the Ethernet interfaces on the VM instance. The public IP address is assigned to the public side of a 1-to-1 NAT gateway. This gateway does the translation from a public IP address to the private IP address that is assigned to your VM instance.
Share this information with the software vendor. As the cloud grows in popularity, they will need to find another way to authorize their licenses.