Assume that you have deployed a Virtual Machine in GCP and now, you can see 2 IP address. One is for the internal usages (Internal IP) another is to expose to the world (External IP address).
Using the External IP address, one can see changes to your Virtual machine or server.
These are the few thing you need to remember regarding them:
Internal IP address remains despite you stop the Virtual Machine.
But External IP address gets generated when you create a Virtual machine or run a stopped Virtual Machine.
Internal IP address is created to work for internal purposes where External IP address is created to show the world your works 😉.