On connecting my on-prem network with GCP VPC using GCP VPN. From the on-prem network can i access the resources in GCP VPC using the internal ip address of resources.
If the answer is yes, does this apply to all VPN's in general.
I have searched this page for "internal" but found no clue - Cloud VPN overview
Yes, it's the principle of a VPN: bridge 2 networks, through the public internet, but with encrypted communication to keep the traffic secret.
Of course, there are limits and constraints: IP range overlap, routing, network announcement (BGE protocol if supported), firewalls,...