Statements must include either an Action or NotAction element that includes a set of actions. When the element is empty, the policy statement provides no permissions.
In AWS Console -
In Terraform -
References:
https://docs.aws.amazon.com/IAM/latest/UserGuide/service_code_examples_iam.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy