Terraform - Starting From The Basics - Part Two

If you run the commands mentioned in my first article, there's a file generated after final execution with an extension .tfstate. This is the status file. This file keeps track of all modifications you do inside your .tf file, after the very first execution. So you will get historical information of the changes you are doing in your infrastructure if you use terraform to run your infrastructure needs.

source https://www.c-sharpcorner.com/article/terraform-starting-from-the-basics-2/