`terraform` block — settings for Terraform itself

terraform {
  required_version = ">= 1.5.0"
  
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
  
  backend "s3" {
    bucket = "my-tfstate"
    key    = "infra/terraform.tfstate"
    region = "eu-west-2"
  }
}

This block doesn't create anything in AWS. It configures Terraform itself: what version to use, which providers to download, where to store state.