Setting a Principal in an access policy will effectively grant users, accounts, or services with access to each S3 bucket. For more information on how to properly assign a Principal within the S3 bucket policy, see the AWS S3 documentation.
References:
https://docs.aws.amazon.com/AmazonS3/latest/userguide/s3-bucket-user-policy-specifying-principal-intro.html
In AWS Console -
In Terraform -
References:
https://docs.aws.amazon.com/AmazonS3/latest/userguide/s3-access-control.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket_policy