diff --git a/README.md b/README.md
index 8e44d5d..c3d4b00 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ Using the -var flag, you can pass variables directly to the terraform apply or t
 Example:
 
 
-```terraform apply -var="project_id=variable-tf-demo" -var="region=us-central1" -var="zone=us-central1-f" -var="image_name=debian-cloud/debian-10" -var="instance_type=n1-standard-4"```
+```terraform apply -var="project_id=$PROJECT_ID" -var="region=us-central1" -var="zone=us-central1-f" -var="image_name=debian-cloud/debian-10" -var="instance_type=n1-standard-4"```
 
 Environment variables:
 Set Terraform variables using environment variables by following the naming convention TF_VAR_variable_name. This method is useful for storing sensitive data or when using CI/CD pipelines.
@@ -19,7 +19,7 @@ Example:
 
 ```
 export TF_VAR_credentials_file="credentials.json"
-export TF_VAR_project_id="variable-tf-demo"
+export TF_VAR_project_id="$PROJECT_ID"
 export TF_VAR_region="us-central1"
 export TF_VAR_zone="us-central1-a"
 export TF_VAR_image_name="debian-cloud/debian-11"
@@ -34,7 +34,7 @@ Example (terraform.tfvars.json):
 ```
 {
   "credentials_file": "credentials.json",
-  "project_id": "variable-tf-demo",
+  "project_id": "$PROJECT_ID",
   "region": "us-central1",
   "zone": "us-central1-a",
   "image_name": "debian-cloud/debian-11",
@@ -46,7 +46,7 @@ Example (terraform.tfvars):
 
 ```
 credentials_file = "credentials.json"
-project_id       = "variable-tf-demo"
+project_id       = "$PROJECT_ID"
 region           = "us-central1"
 zone             = "us-central1-a"
 image_name       = "debian-cloud/debian-11"
@@ -59,7 +59,7 @@ Example (variables.tf):
 
 ```
 variable "project_id" {
-  default = "variable-tf-demo"
+  default = "$PROJECT_ID"
 }
 
 variable "region" {