A VPN gateway is a type of virtual network gateway that sends encrypted traffic between an Azure virtual network and an on-premises location. The encrypted traffic goes over the public Internet.
This architecture is suitable for hybrid applications where the traffic between on-premises hardware and the cloud is likely to be light, or you're willing to trade slightly extended latency for the flexibility and processing power of the cloud.
https://learn.microsoft.com/en-us/azure/architecture/reference-architectures/hybrid-networking/
