How to define the principal for an AWS policy statement?

Question

I'm starting from http://awspolicygen.s3.amazonaws.com/policygen.html to create a policy that will grant upload rights to a specific S3 bucket for a list of users. I'm not clear on how I define who those users should be.

The docs refer to a principal as "a person or persons" without an example of how to refer to said person(s). One assumes "email address" and the policy generator will accept it, but when I paste the generated statement to the bucket policy editor, I get:

Invalid principal in policy - "AWS" : "[email protected]"

Full statement:

{
  "Id": "myPol",
  "Statement": [
    {
      "Sid": "Stmt130",
      "Action": "s3:*",
      "Effect": "Allow",
      "Resource": "arn:aws:s3:::myBucketName",
      "Principal": {
        "AWS": [
          "[email protected]"
        ]
      }
    } ]
}

Answer 1

A principal can be another AWS account or an IAM user. These docs are helpful Specifying Principals in Bucket Policies and Integrating IAM with S3