Hi@akhtar,
You can use the google_project_iam_custom_role resource in your Terraform code. This resource is used to create your own customized role as shown below.
resource "google_project_iam_custom_role" "my-custom-role" {
role_id = "myCustomRole"
title = "My Custom Role"
description = "A description"
permissions = ["iam.roles.list", "iam.roles.create", "iam.roles.delete"]
}