terraform reference resource in another resource code example

Example 1: how to define provider in resource block

# default configuration
provider "google" {
  region = "us-central1"
}

# alternate configuration, whose alias is "europe"
provider "google" {
  alias  = "europe"
  region = "europe-west1"
}

resource "google_compute_instance" "example" {
  # This "provider" meta-argument selects the google provider
  # configuration whose alias is "europe", rather than the
  # default configuration.
  provider = google.europe

  # ...
}

Example 2: repetitive resource use in different region terraform

####Repeat Resource block and launch in multiple regions

provider "aws" {
  region     = "us-west-1"
  access_key = "PUT-ACCESS-KEY"
  secret_key = "PUT-SECRET-KEY"
}


provider "aws" {
  alias = "mumbai"
  region     = "ap-south-1"
  access_key = "PUT-ACCESS-KEY"
  secret_key = "PUT-SECRET-KEY"
}

resource "aws_eip" "eip1" {
  vpc = "true"
}

resource "aws_eip" "eip2" {
  vpc = "true"
  provider = aws.mumbai

}