Site-to-site VPN vs point-to-site VPN

In point-to-site, you have to connect to the network you want to access manually. Usually, if you log-off or restart the workstation it loses connection, and you have to reconnect every time. It's common to use this type of VPN when we are working remotely, and we need to access our company assets. The channel is bi-directional, but it's 1-to-many.

Site-to-site is used when you want to connect two networks and keep the communication up all the time. It's also bi-directional, but it's many-to-many and stays up no matter if your server/workstation is running or not because the connection is established through a network gateway and not from the computer operating system.

In Azure, the Virtual Network Gateway is the platform providing both functionalities. You can configure site-to-site to connect to your customer network. If this network is not running in Azure, they usually have an appliance to establish dedicated tunnels. As long as it supports IPsec IKE, you are good to go.

If you are using the VM in Azure as a workstation, then point-to-site may be enough, but if your application needs to get data from the customer database automatically with or without someone logged in the VM, then site-to-site is a better approach.

A better explanation can be found here